Not really necessary here in this forum. It's for the US since that's where FL originates.
There are other b/s/t sub-forums for Canada, Australia and Europe. Buy, Sell, Trade, Free
How many are you looking for?
I sell mine for 0.50 cents a snail because although they breed rapidly I can’t seem to keep up with my friends demand lol I think I can manage to get you 50 snails right now for 25$ that includes shipping cost. If you put about 10 of these away and let them be for roughly 5 months you’d have a pretty consistent supply. These are bladder snails by the way.
Buy some on ebay and keep them in a 10 gallon in a sunny window. That should keep your puffers happy