need help with my htc evo plan?

[dAM IT]

so i bought an htc evo but i wanted to connect it with sprint but on a prepaid service plan.or i want to flash and get it working with metro pcs but idk is the service good? i live in los angeles.i dont want too get tied up with a two year contract.with wat other companies can i connect my phone with on a prepaid plan .or ill be selling the phone