you're = you are, i.e. "You're the best friend I ever had," or "You're a dork."
your = denotes possession, i.e. "your shirt is dirty," or "your dog is cute."
Look at this item and tell me what you see. And they're selling it for $19.50. Who let this one sneak by? It didn't even sneak---this is glaring. I'd crawl under a rock if I'd been the one responsible for this. I'm also quite certain it doesn't come down to any one person, but society as a whole. People in this country don't even know the proper rules of their native language. It saddens and scares me.
Hit the "View Larger" button once the item pops up. Tell me what you think.