Here's a CC Forum guy who used the FMCA program and his tire price:

Here is the all in cost per unit - Tire $553.00, FET $52.83, State sales tax
$51.31, mounting $25.00, balancing $45.00 and "shop supplies" $4.25. Total -
$731.39

I think he got hosed on the mounting & balancing, but the 315's were 553.00 before taxes and labor.