I've used Target a few times, and it's very inexpensive. Just wait until you get a coupon - I see them all the time in the mail, in magazines, and newspapers....and I'd imagine you can find some online as well. I used to always wait until I found one with "free sitting fees" (we have five people in the family, and the normal fee is $10 per person, which can really add up!), but I haven't seen any of those for over a year - they might not offer it anymore. Regardless, purchasing the prints themselves is very inexpensive, especially if you find a 40% off coupon. I always got something like an 8x10, a few 5x7s, and a bunch of wallets for under $20.
Re: Sears/Target portrait studio