I get mine from Bostick and Sullivan. High quality, consistent quality, and dependable friendly people to deal with.
100 grams to 200gm of Silver nitrate is $1.29/gram (At $129 for 100 grams, that is less than half of PF's prices). 200gm to 500gm is $1.17/gram. Over 500gm is $1.10/gram.
I usually buy it 30 grams for $39 -- no extra shipping charges at this amount. Tho there was no extra charge when I last bought 50 grams from them.