if your fish shop wants them, ask either exchange for fish or fish products or about 50p each,(my fish shop sells them for £1 each) that isnt much but dont be too greedy and 50p times 100 is alot.plus if the fish shop likes the price you sell them at, they might take your next lot of you.i didnt sell any snails back to my fish shop as personally i hate snails,golden snails arnt so bad, the common ones i was rid of, but thats just me, i know other people love them,