I know the industry pretty well, and obviously depending ont he quantity that you need and are looking for, I would buy from 1 of these 3 places.
These are probably your 3 best bets when it comes to best price and high quality, no scammers.
I have also noticed that people here in this forum buy only a very small quantity at a time. Would it be worth it to pay less per sq ft and just buy more than u need and have it as your reserved? There is an unlimited amount of uses for this material, trust me, it is not that worst thing to have laying around the house. You will always find a way to use it.