I'm trying to get cheap service - I'll be at college so I won't need data (I'll have wifi). I'm wondering if it's possible to buy a cheap phone on another network (my plan is to use Virgin Mobile) and then buy an HTC Evo, and put the SIM card from the Virgin Mobile phone into the Evo (I was going to buy the Evo with a Sprint contract and then cancel to subsidize). I know that certain networks are incompatible, so will this work? Are there two networks that I should try this with that WILL work? I'd like to stick with Virgin Mobile if at all possible because they have a 20$/month plan.