There are loads of adverts on there where no price is mentioned, but you can bet your life, call up and the animals are actually for sale. It's obvious which ones.
Is it 'allowed' for people to have big cats as pets? Not ethically no, but people still do it. There are always those who will want exotics. Unless they are on the endangered lists or there is a ban in place, there is not much to stop them.
In case you missed this.. please report. I dont think this will ever stop!!
http://ajman.dubizzle.com/classified/pets/pets-for-free-adoption/other/2011/5/19/male-marmoset-14/?back=Y2xhc3NpZmllZC9wZXRzLw%3D%3D&ps=4&page=7