It really, really depends. Shelters are awesome, and you can find loving companions, but on the downside, they often have health problems and need a lot more attention than a ferret from a breeder. If you do go the shelter route, I'd definitely say get a pair, as shelter fuzzies most often need a constant companion. A little one from a breeder, raised alone and with all the attention you guys can give, doesn't need that constant friend.