Okay I'll add my two

in here:
Glycerin with Nicotine in it has a virtually unlimited shelf life if kept frozen.
The above being said Nic base has been and will be about $50.00 per liter for 100mg/ml ...I don't see it falling much in price any time in the future.
There are some well looked over facts regarding vaping:
There will be NO regulation on hardware.
There will be NO regulations on vaping supplies that contain no regulated substances ( Nicotine ).
As I said in an other post any more than there are regulations on Coffee Makers!
At best the FDA would regulate who and how e-liquids are manufactured and tax the nicotine therein.
The above being said, how much do you vape?
If you are a DIY, buy as much as you want, eventually you will run out....(well unless you own a freezer farm)..LOL
It's not much different than saying what if there is a natural disaster and one cannot get fresh water or food supplies for "x" number of days or time.
It's not the fact that "if", it's more over when!
Rest assured BT, BP will work its tentacles into vaping, how bad it will be, who knows?
As far as VG vs. PG... VG base is better because almost all e liquids are a combination of the two, and it is easier to thin out VG with PG than the other way around (IMHO).
For most 100mg/ml is a good concentration because you can dilute is a necessary.
Just remember your vote does make a difference!
If we do not get fresh blood into politics nothing will ever change!