Sorry for the late response, tonight was movie night with friends and I forgot that. They've just left though.
Anyway, thanks wv2win, I actually intended to ask what mg of nicotine to start with when I got back on here and see that you've already answered that.
I was a long time smoker and I got a bottle of 12 and 24 in the same flavor. I figured I could mix them together for 18, or add to the 12. For me, the 24 was perfect.
The nicotine level you start with in the beginning to get you off cigs may not be the level you stay with. Just like flavor, it's trial and error with juice. So start with small bottles.
Purchase juice from a juice vendor. Along with nicotine, the juice is composed of pg or vg. Some like a combination of the two. PG gives more flavor but can be harsh to some and irritate their throat, it does give more throat hit. VG is thicker, gives more vapor, less TH. Using cartomizers, some juice vendors recommend 70pg/30vg, or 80pg/30vg. Some people like all VG, some like all PG. Some juice vendors allow you to pick the ratio of pg/vg and nicotine strength.