I've been vaping 100% vg for 6 months mixing my own because i honestly have no desire for throat hit and i really want to be able to adjust my mixes to taste. i really prefer a smooth cool vape so i drip on an 801 atty with 3.7v 14650 epower, and a 5v usb passthrough at my desk. when I go out though i love the convenience of carto tank setup. I do 20% flavor into 24mg 100%vg and then add 5% distilled water to thin it just for my carto tanks. so this lowers the nicotine down to like 19mg.
Mixing your own is absolutely the most affordable way to vape. If your just getting into mixing I would agree that you stick with 24 or 36mg starting out so that you don't have to worry about having super high 100mg nicotine floating around. I would also recommend getting small amounts of flavoring to see what you like, and perhaps make a document or spread sheet with the mixtures you have tried and comment on what you like so you can nail down what mixtures you like best over time. Definitely get a 10ml syringe rather then counting drops.
Also there are huge differences in costs from site to site for both nonflavored vg, vg w/ nicotine, and flavorings. My current favorite is myfreedomsmokes.com for VG and flavorings and then madvapes.com for hardware.
Our Unflavored Smoke Juice (Nic. Juice, Nicotine Juice) - My Freedom Smokes
oh, and FYI I came across this thread looking for good alternative sites for buying 24mg 100%vg, but still think myfreedomsmokes.com is the best I've found.