Exodons locally are $10/ea
1.5g per exodon I'd say would be nice, 2g if your feeling generous. If you know a LFS in your area that carries them or at least can order them, go in and talk to the manager or owner and see if you can make a deal. Sometimes they are willing to negotiate. I told the owner of the one by me that I don't want to get fish for free but I don't want to pay 100% mark up. Usually won't work if you want one fish but if you go in and say you want 3 dozen they might be more willing to work with you. It's all in how you approach them about the subject. Kill 'em with kindness