Cricket to Droid X

[imdana]

I just bought a droid x off a guy on craigslist...it is already flashed to cricket. When i went to activate it (i already have a cricket plan, just switching phones) the guy said i need to re-flash the phone plus activation. Costing upwards of $50. Is this true? Can i do any of itmyself? For free? Please any advice appreciated...i have the phone and a charger, totally ignorant regarding android phones as this will be my first. Thanks in advance...if anyone knows how to activate myself (for free) and or if i have to re-flash or not. Just to repeat myself...