I doubt you will find a cheaper price for a new topper/canopy through any online dealer. Sometimes you may get lucky and locate a new topper on Ebay.
I would suggest searching the local area for a quality used topper, and then look at the dealer pricing in your area. You may even find a drive (1+ hour) may save you more then a local dealer.
If you have any problems it's nice to take it in for warrenty to the dealer.
Look at this auction:
http://cgi.ebay.com/ebaymotors/ws/eB...category=33655
Just cut and paste the address or use the number:7979026198 in the Ebay search.