Try myfreedomsmokes. Hell, you can get 500ml of 100mg nicotine in your choice ratios of PG and VG from them for $50 If somebody can point me toward more pure base ingredients than those sold by MFS, I'd love to hear about it.
Interestingly, you can get nic for half that price- from MFS
The $50/500ml price is delivered in glass bottles. They also sell a liter for $50 in an HDPE bottle for $50 as an everyday price, and occasionally put it on sale for $40. I've bought two of those liters. I bought some amber glass bottles to break it down for freezing. Anyone thinking about long term storage would probably want to break down even a half liter, so that the chilled back stock has as little air in the bottle as possible. So in my case I would have had to buy those bottles anyway.
As far as I know, they are putting the same nic in either put up. In the more expensive glass bottles they sell a full liter for only $65. Although it would otherwise not make a lot of
sense to buy a whole liter, there are so many concerns about taxation and whatnot coming up that I think it does make
sense to buy at least a liter, especially for the price. There is a thread here discussing a proposed Indiana state tax that would come out to $830 per liter for concentrated nic. And a few other states are testing the waters with absurdly high tax proposals.
I have not found a cheaper source for nic than MFS's 1 liter HDPE bottles, at least from a reliable source that is well known and discussed here.