I don't really get Big 5 Sporting Goods. They advertise low prices, but when you go in they seem to only carry last season's styles. It almost seems like they are a sporting goods outlet. That being said, if you don't need the latest styles this is a good place to go and for basics like workout shirts and shorts. Plus, the clearance racks will often have the stuff you wanted a few years ago but might not have felt like paying full price for.
As for sporting goods, the problem is that the name-brand stuff isn't that much cheaper than going to a store like Sports Authority, Sports Chalet, or Dick's.
Overall, it's worth a visit, but don't set your expectations too high.