That's part of the fun.Not to mention, most people raise the prices of the animals, because other people raise their prices. Its an endless cycle of not having credits and needing them. Eventually, I expect the in game animal market to crash, since the prices will be so high, that eventually no one will be able to buy animals at all.
but in all seriousness I don't think it will ever get that bad & I don't think price gouging is happening as often as we're fearing. I see far more people offering up generous pricing than greedy ones.