instead of using onchange for the select lists, add a calculate price button, and run the look up on the calculate price button so that the look up only occurs once the user has made all selections and presses the calculate price option.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.