I looked into it at my local discount tire and they would charge $16.00 per tire. Additionally, Discount Tire Direct is $12 more per tire for the Duratracs I was looking at in the local retail store, so when all was said and done there wasn't really that much of a savings.
YMMV depending on what you can get them mounted and balanced for, but unfortunately it wasn't that great a deal after doing the math.
On a side note, there's also a $60 mail-in rebate promotion going on from Goodyear for the Duratracs through May 31st.
Tire Coupon | Goodyear Tires