A friend of mine built his own bed cover for about 130 dollars Canadian (prob $90 US). I thought it would look like crap but I was really impressed with the finished product.
He bought 3/4" mdf and had the guy cut it to fit flush with the bed rails. Then he had that cut into three equal sized sections (you could leave it all one piece if you want, but 3 pieces looks really good and is functional).
Sand down, and round any rough edges
Then go to a fabric store and get some marine grade vinyl. Wrap the three equal pieces in your vinyl. Attach it with spray adhesive and staples.
Now you have to rig up some brackets to make the wrapped pieces sit flush with the bed edge. Any hardware store will have some L shaped brackets that will work. the worst part of the install is that you probably would have to drill a few holes to bolt your supports up.
If you live near a hardware mega store that does the cutting for you this project is pretty easy. most fabric stores have sales on all the time and have vinyl in 2-3 colors so you could get creative. for the money you will need to spend I think you will be really happy.