I'm not sure if you're aware of these two things:
Steer tires cannot be retreads. You can however retred your current steer tires, and use them on the rear.
If the current carcase of the tire you want to be retreded is not in good shape, you cannot have it retreded. I've noticed a lot of older tires have cracks and other imperfections that may disqualify a tire from the retread process.
if i remember, i'll call the tire place on monday and get a price to retread my tires. That should give a good ballpark for your tires.
There is a goodyear facility near my house that not only sells/services large truck tires, they retread them right on site.
I purchased a used steer tire from this company for $75.00. It has lots of tread on it.
Quis custodiet ipsos custodes (who will watch the watchmen?)