I've got a Truxedo Truxport roll up on mine and like it pretty well. It can be a little tough to release on occasion, but for the price I am satisfied. I think I paid $280 a year ago for it, I don't know what they run now.
I had a Pace Edwards Jackrabbit cover on my Colorado. This gives the security of a hard cover as well as the convenience of a soft cover. I'll see if I can find pix.I thought about the Jackrabbit when I bought my Bakflip...its a nice cover. But I'd bet it won't be in the OPs price range given that it cost about 4x what a soft cover does.
edit: huh, not sure what I did to make the quote not work. oh well.