I buy my nic in PG. At first I didn't understand that nic was sold in PG or VG or in some cases, a combination of both. So when I was looking to place my first nic order I didn't understand why I had to choose. It's is a bit complicated and took me awhile to wrap my head around it LOL. You can buy 100mg nic in PG and then use more pg or vg and flavoring to cut it down to a vapable mg strength. The tasty vapor site helped me to understand it all. There you can order (for instance) a 1oz bottle of waffle flavored nic juice in 12mg and vape it out of the bottle.. OR you can order it at 48mg strength and then use the flavored "doubler" (which is actually flavored PG and VG) to cut it to your desired strength. I don't know if you even can (why would you want to?) order nic in any other form.
edit: WoW! I just read the other posts on the guy who bought the crazy high nic! I just remember how puzzled I was when trying to order my first nic and didn't realize that it came in PG and/or VG.