I doubt that they would have any pedals, much less 1/2 inch pedals. Go to a bike shop that sells bmx bikes. If you're looking for platform pedals, you shouldn't have too much trouble. If you're looking for clipless, you may have to try ebay or internet sales.
Yes, I think so. I bought pedals at a Walmart about two years ago. I think I paid $10 or $15 for them. I don't live where you live, but I think most Walmarts have about the same stuff. Good luck!