My lfs has loads, about £15 each though, they have the usual brown, black, pink and Golden which are my personal favorite.
The only thing to worrie about with them is stress.
They get really stressed quickly and develop white fungus all over themselves and the only medication that you can use is myacsasin probably spelt wrong but it does shift it.
They will eat almost anything, mine eats : Bloodworm, Lancefish, Silverfish, Earthworms etc etc and will become tame after only a week or two so they will rise to the top and quite happily hand feed from you sucking at your fingers