I'd either lower some of your prices on the PCs or remove them. Most people don't bring $150-$200 to a yard sale, and even if they would, those aren't really worth what you're asking. If I were you, I'd remove the PCs altogether and try to sell them on eBay/Craigslist. The rest of the prices range from pretty good to barely passable. I'd say to try to lower everything a little, I mean, this is a Yard Sale, not a CL ad.