Hermit crabs

About 9 months ago Will chose hermit crabs as his behavior reward. Little did we know it would turn into a 100 plus dollar expenditure. Their habitat is quit nice... Will picked out crushed shells for the bottom of the tank, a crocodile skull and a coconut hut. These were the first two crabs that we had... the small one died... and we got several more... but unfortunately those all passed as well. We are thinking that maybe we will try again when Will is a bit older and can help take care of them.