Who sells marmoset monkeys?

Anyone who is after a quick profit and likes animal cruelty. Marmosets, like all primates, do not make good pets. They are not domesticated (or tame). In addition, marmosets spray (pee, a lot, smells musky!), bite, get aggressive over their territory, and need a companion of the same species.

You do not want to buy a monkey, get a dog/cat/hamster. Cheaper to buy, cheaper to take to the vet, and it won't make your house smell from their spray, or bite you (and then end up being put down, or taken to an already over-flowing primate sanctuary).