I need a good camping backpack for $40 or less....?

I need to get a backpack that's durable, at least somewhat waterproof, and has a lot of space inside. I would like to stay inside the $40 price range, but if it's just super awesome for that extra $5 or so, recommend it. It definitely has to be from REI or 's because I don't live near any other sporting goods stores. And no I will not buy online, I like to see and feel before I buy.