Check out Craigslist you might find what your looking for at a fraction of the cost.
Very true. I had an '89 F150 with a cheap aluminum cap that rattled and I junked that one because I wanted a fiberglass cap. Ford had changed the box size, so nothing nearly new off Craigslist was going to fit. Then looking at Autotrader.com I found a fiberglass cap the exact same color on an old truck at a dealership. A road trip and $75.00 and they were happy to take it off their truck for me. Lots of used truck places remove the caps for some reason before they sell the truck.