I mentioned
http://e-liquid-recipes.com/ above and wanted to impress on you something else good about the site. You can search for both recipes and individual ingredients. For example, if you have some Vienna Cream you can search for that and it will show you every recipe that has Vienna Cream. From there you can sort by most popular and then find one that you have all of the ingredients for.
What I tend to do is find a recipe that I am missing an ingredient to and substitute something similar. As a very basic example, if I wanted a cheesecake recipe it might call for Strawberry. Maybe I don't have Strawberry but I have Raspberry and it's by the same company. In theory the flavors should have the same "power", though that is not always the case. So I'll make a Raspberry Cheesecake batch.
It's interesting how cheap the flavors are considering how long they last. You can get a 10ml flavor for $1.95 on many sites. At this point I deal in mostly 30ml or greater when buying and that runs usually around $4.95 or so. On other things like Vanilla Custard, which goes into almost everything, I only buy in 120ml.
For PG and VG I went to Bulk Apothecary and bought a 10 lb bottle of VG for $14 and 8 lb bottle of PG for $19. PG is lighter so the bottles are the same size. I have about 1/4 of the VG left after around 6 or 7 months. Just pour it into a 60ml mixing container and draw from there. Add more as needed.
I do the same with Nicotine. All of my recipes are 55ml and so they all call for 1.65ml of Nicotine (100mg/ml VG for a 3mg/ml mix). So pour it into a 30ml container and draw from there. I get roughly 12-13 recipes done at a time that way, and based on my mixing yesterday, twelve mixes is the maximum that my brain can get through in one day.
I mix once a month. By the time one set of mixes is finished the next batch is ready for use. Then repeat. Between that and the occasional store buys I'm never out of e-juice. I don't like to buy store bought eliquids, but some liquids I like just don't have a suitable clone. Beard #5 and Brindle are two examples.
For calculations I use
http://www.steam-engine.org/juice.html, but they all pretty much do the same thing. I also copy each recipe into an Excel file for future use - remembering to include the percentages since copying the recipe doesn't include that. So if you want to double your recipe you just double each ingredient, but if you want to turn a 55ml mix into a 75ml mix it gets more complicated. I'm sure a formula in Excel could do it, but it's easier just to re-enter the percentages into the steam-engine site with the new higher volume.
