How to flash iphone 4 to boost mobile?

We bought a iphone 4 off craigslist. And its already seems to be flashed to boost. But when we called boost they said they can't do anything. We found a place that will do it, but its out of the way and cost 40 bucks. In the corner it says boost. Is there something i can do. I'm good with a pc so any help is welcomed

Boost Mobile does not allow outside phones at all, regardless of flashing. That is why the phone was sold. Boost Mobile is a CDMA carrier, and they maintain a list of allowed ESNs, and if the phone is not in their system (such as this one), they will not allow it to be used.

Boost will not add outside equipment. You will have to use an active boost phone esn and have it programmed to the iPhone. (You will find many posts about the legality of this since it was commonly used to defraud consumers.(taking an esn/imei and programming it to a different handset and it working like it was the original phone from the account) Then making sure the settings are modified to allow data to be correctly transmitted and received. I'm sure if you check youtube you will find the exact process. Check one of the guides for Pageplus, or other and just replace the settings with the Boost mobile settings.