I want to get a t-mobile prepaid plan however their prepaid phone selection sucks. Can I just buy a phone from ebay (t-mobile or unlocked) and use it with the t-mobile prepaid plan? I'm planning to get either a blackberry or a touch screen phone. Also are texting and web included?

I already have a t-mobile prepaid sim card that I used with my sidekick last year. But I have not refilled it for over a year. Can I continue using the same sim card? Thanks.