I'd recommend John Hopewell for cages:
http://www.johnhopewell.co.uk/
I've bought two off him and they've been excellent.
Otherwise get good quality pellets and hay (timothy or alfalfa), preferably the same type as the breeder used. Oh and buy from a good breeder please, i know a few if you need any advice, don't go anywhere near a pet shop. I've got a standard grey and an ebony for £100, typically a coloured will cost a lot more due to the rarity in the breeding process.
Be careful what you feed them because they have very delicate internals, i give them shredded wheat as a treat as it's the only cereal without additives and they go crazy for it, they have a sweet tooth as well so only give sugar based snacks like raisens in moderation, gogi berries are good.
Otherwise buy a proper quality chinchilla bathing sand, not generic stuff from your local B&Q.
Make sure you give them lots of toys, especially things to chew on as many chins have teeth problems, mine have got a pine box that they like to hide in when it's light, plus a few ledges and chew toys.
Best toys i have...
Hammock!! -
http://www.hammockyhammocks.co.uk/
Flying Saucer Wheel -
http://www.fswheels.co.uk/
Chinchillas on their own can get very lonely as they are community animals, a lone chin will bond with you if you're willing to play with them on a daily basis and have a lot of patience. However it's much better to get a couple of animals, they'll not be as house friendly but they'll be happier animals overall, once they've got used to you it'll be fine.
Drop me an e-mail in my trust if you want any advice, my family have had chinchillas for 18 years so i'm fairly clued up for an amateur.