It's easy for us to tell you, "You can save a lot of money making your own e-liquid", but it's not that simple. DIY takes some upfront capital, lots of experimentation, sometimes multiple orders from multiple suppliers, failures, handling hazardous materials, and patience. First you should probably figure out exactly why you want to make your own e-liquid.
There are lots of reasons, and none of them are exactly bad, but some of them may be unrealistic or invalid for you. I don't know your situation, so the answer is always, "it depends."
It's true that finished DIY juice is usually cheaper by volume than even the most basic of commercial juice. I say "usually" because it's possible to pick up some truly awful stuff at $0.10/ml, and a juice using a lot of expensive flavorings can easily go over $0.20/ml. Granted the expensive stuff "should" taste better, but taste is subjective and maybe it doesn't matter that much to you.
However, the combined cost for your super-awesome homemade super inexpensive e-liquid isn't the whole story. You need to spend money upfront, sometimes hundreds of dollars on flavors, nic, bottles, labels, safety equipment (goggles, gloves, etc) and either volumetric (syringes, pipettes, etc) or weight mixing (scale) equipment… all the things that you'll find elsewhere in this wiki, and then some. And then there's the cost of the juices that fail completely, the stuff you spill, the stuff you give away to your friends because you need feedback, etc. etc.
It will pay off… eventually. If you're really curious, calculate the amount you spend per week on juice, compare that to the money you're going to spend to start up, and see how long it takes to get your money back. If you're super-budget conscious and spend $15 a week on liquid and your initial hardware capital (mixing stuff, etc.) costs you $40 and your juice cost is about $0.10/ml, it should take you about 3.5 weeks to recoup your costs. That's not always true, of course, since you will likely vape more on flavor tests and the like, and it doesn't quite cover the investment in bulk liquids you made. If your total outlay including flavors and nic base is closer to $200, it's more like 15 weeks. Still a good deal, but it's not the instant savings many imagine it to be.
What if you want to save money because you would like to clone (that is, make an identical copy) of a premium juice? Mixers of reputable premium lines spend a lot of time developing their flavors, and you're not likely to duplicate their recipes with your 6 sample flavors and a recipe you found online, though there are some famous recipes out there that can be similar. With some (ie. a lot!) of trial and error, you could come close, however and be completely satisfied.
If this is your motivation, then DIY is the best option for you. Note that any reputable juice vendor will tell you if they have a specific ingredient in their mix like diacetyl, but sometimes they don't know, underestimate the toxicity of an additive, or are just scum who don't care. Most large scale companies will never reveal their flavoring components, however. DIY lets you control your ingredients to the extent that you understand your components. Titrate your nicotine base, carefully investigate all your flavors, determine your ideal PG/VG ratio, and not resort to non-USP solvents.
That may not be quite true; it might be more accurate to say, "Nobody makes the flavor I want at an affordable price" or "it's too costly and time consuming to find a juice I like." There are some flavors that are notoriously difficult to mix, or nigh-impossible. Take sour properties, for example. For picky palates, even with the wide array of flavor profiles available in commercial juices, there's still the hit or miss "is it any good?" problem. With DIY, you can toss the odd test batch of something new you made for pennies per ml rather than buying a 30ml of some juice and finding you can't vape even half of the bottle. Or you can hate-vape through the mix, shedding tears the entire time.
Not to say that it can't be done, but making a juice that has mass appeal, or even niche appeal, and being able to support commercial production is very difficult. Do you have an LLC? Can you afford insurance? Can you take credit cards? Do you know B&M owners who will stock your stuff, whether wholesale or consignment? How good are you at promotion? My advice is to start out trying to make juice that you and your friends/family like, see if a wider circle likes it, and go from there. As a side note here, if you reside in the United States, as the situation sits now it is nearly impossible to introduce new e-liquid on to the market due to overwhelmingly expensive fees and strict regulations on all tobacco products. Basically, if you live in the US, it's not going to happen. Even more so with the PMTA deadline fast approaching.
It seems more likely that nic may become more expensive as it becomes more regulated. The proposed nicotine tax bill is evidence of this.A bigger concern might be the unavailability of your favorite juice provider(s) due to increased compliance costs. Fortunately, nicotine base is relatively inexpensive, for the time being, and will last in brown glass in the freezer for several years at the very least, and you don't use all that much. Keep an eye out for nicotine sales from vendors who aren't terrible and take a shot. Another side note here; if you're in the USA the FDA is attempting to regulate flavored tobacco products and flavored e-liquid unfortunately falls into this category. It seems unlikely that the multi-use flavorings that we use will be outright banned, but prices or taxes on them may very well increase.
It is. This may be the best reason of all.
It can be! DIY only has to be as complicated as you want. Sure you could develop all your own flavors and experiment with all different kinds of concentrates and create new recipes, but you can also cherry pick some recipes online with flavor profiles you think you'd like, and buy concentrates accordingly, and then just mix by numbers from there. Doing DIY is somewhat like owning a 3D printer. You may find that you become a recipe making genius, but if not there's a whole world of recipes out there that other people have created.
There are a few. It's easy for an experienced mixer to say, "Oh there are no downsides." It's possible that they were a natural when they started, but maybe they forgot how terrible they were when they started.
Nicotine is toxic. Never forget that. I think to myself, "Nicotine is toxic" the same way I think, "Every gun is loaded." Yes, you might spill some on you and just get a head rush for a while, or no ill effects. Why do you even need gloves? You never spill anything. Well, that's true, until you do. Safety equipment is not there to keep you from having to pay attention; it's there to save your ass when something unexpected goes wrong. It will also kill children and pets in much lighter concentrations. It will also kill idiot roommates who don't know what the hell they're taking out of the freezer late at night when they're snooping around for your vodka bottles. If any of this makes you uncomfortable, you might think twice about handling high concentration nicotine in your household.
Bottles. Flavors. Test vials. Liter or gallon jugs of propylene glycol and vegetable glycerin. You should ideally have a separate room where you work on this, or at least a tool bench, lab bench, or even just a rack of trays to hold all of the equipment that you're going to be spending your money on, if only to keep yourself from tripping over things. A freezer to store nicotine for long term usage is also recommended.
If you think waiting two weeks for your bottle of liquid to steep is annoying, wait until you have twenty-something tester bottles of juice sitting in a dark box somewhere. If you don't mind the wait, you might not have this problem, but generally people who DIY tend to spend a lot of time dialing in flavors and experimenting. It's one of the reasons we do it in the first place. Not all flavors require a steep, but it may take more time developing something you'll actually want to vape.
Bottom line is: DIY may or may not be for you. If you're in a living situation where nicotine base would be dangerous to keep around, like a home with small children, it may be difficult to find a safe place to work, make sure to keep nicotine and other chemicals out of reach of children and pets. Better yet utilize a locking cabinet and store all nicotine and e-liquids locked up.
However, for those of us who want to know what goes into our juice, and those with an eye toward experimental flavor combinations, this may be right for you.You can save up for the initial investment, start keeping careful records, and even if you don't create a recipe that is out of this world, you will have the satisfaction of vaping something you created, something you can tweak to your liking, something that's better than most of the commercial stuff on the market. And even if it's only "as good," it costs you a tiny fraction of what it would in a store, and to me that automatically makes it better."
This is not my original article at all. It was originally written by /u/muranternet and still contains quite a bit of the initial material. It underwent a recent "remix" by /u/RockyHarlow. I added that update not with my own ideas, but with suggestions by /u/brrrbrbr, /u/juthinc, /u/ReeferCheefer, /u/ChemicalBurnVictim, and /u/INTERLINKED, and others. I'm posting it here for easier linking to the wiki/beginner's guide. ~ID10-T