Some of Costco's stuff is pretty good! Last time I was there (I'm not a member, doesn't pay for a single person) with my DIL, I saw quite a few interesting things including a $70 down jacket (getting a lot of attention nation-wide) with high-fill down and plenty of technical info on the label. Andrew Skurka on his blog mentioned finding a pair of carbon fiber trekking poles for $27 at Costco for his fiancee that he thought were quite good. I picked up some pretty good merino wool socks (I wear them all the time, not just for hiking) and a bed for my dog (no, definitely not for backpacking, but every dog bed I've gotten there has lasted 3 years, while one I got at Petco for the same price wore out in less than a year).

As Aimless said, with footwear it's all about fit, fit, fit. All I can do is repeat his recommendation: If they fit you well enough for you to want to take them home, once you get there put on the shoes, put on a pack and hike around the house for several hours. Boring, yes, but you'll be able to return them if they don't fit. Contrary to folklore, you should not have to break them in; they should fit you to start with. If you can rig up a ramp so you can walk sloping downhill, so much the better. Oh, and always try on shoes late in the day when your feet are swollen if they are going to swell. In fact, you might want to go for a nice long dayhike and stop at Costco for a try-on on your way home!