Al Knock has the best reputation for making tops. I think most catalogs sell his brand. I think I paid about $160.00 from a now defunct business about 2 years ago. I paid $400.00 for the install from an excellent shop. I had received quotes up to $1000.00 which I would never pay. While your replacing the top, its a good time to replace the top weatherstrip if it is showing any age.
In my case, the frame for the top was bent and rusted, so I had to spend another $600.00 to repair and replace parts of the frame. Just be prepared for additional expenses that may arise when the old top comes off.