i think you are on the right track.
if your item price is dependent on size, you should create a table incorporating product_id, size_id and price.
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.