Here are the instructions for flashing the Epic 4g to metro pcs: Epic 4g to metropcs/cricket - xda-developers

I've just bought this phone

Clean ESN / Unlocked / Rooted /ICS

iv been using it the last two days off wifi. i went to radio shack boost mobile and metro pcs all said they can not flash phone i need to activate asap.
id like to know; what my options are, whether mms and web will not work with certain carriers and instructions on how to do so.

if metro is not an option willing to go with boost mobile, or cricket.