If you can't afford a new ProCal or FlashCal, check Craigslist or wherever for a used one. But if you go used, do an in-person sale rather than shipped so you can plug it in and verify that it is not still VIN-locked to a previous vehicle.
Another option might be a smartphone app that I've seen talked about in a few posts. Something like $15 plus a cheap odb cable. No idea if it works, but might be worth looking into anyway.
