Whoever you buy tires from should mount, balance, and install them for free. That is pretty standard so don't let them charge you extra unless they're giving you an unbeatable price.
I've found that most tire shops like Firestone, Goodyear, Discount Tire charge about $100 to replace tires if you buy the tires somewhere else and bring them to the shop.
I personally use Discount Tire. They charge $40~$50 to mount tires if you buy the tiress from them and throw in free life-time balancing & patching. And they also match Tire-Rack's prices for the tires. So that usually works out pretty well for me.
If you purchase from them it will be included in the total quote. If you are bringing them in, a reputable shop will be around 1$ per wheel inch. 17" = 17.00
