Where do you get your tires mounted and balanced after purchasing them online?

I was interested in purchasing tires from such stores like www.tirerack.com, but after I realized that mounting and balancing each tire costs about $20, and after shipping costs, basically the savings are wiped out (or I may save $10-$15 overall, and have to deal with lugging the tires from my house to the shop). Besides, I wouldn't get free tire rotations either. What have you done? I saw that walmart would mount tires pretty cheap, at only $3.50 per tire--check out http://www.walmart.com/catalog/catalog.gsp?cat=495845. Have you had experience with them?