I am interested in starting a small price comaprison website in my local area. The site should compare prices from 20 suppliers, selling an identical product in 4 different quantities and some suppliers only deliver to certain post/zip codes.

What would be the best way to set up this database in phpmyadmin? table for supplier names with IDs, then table with prices per quantity per supplier and then table detailing post/zip codes each supplier delivers to?

I also need advice around the customer interface. I'd like 3 dropdown lists on my home page, list 1 gives county options, list 2 would then open in different frame showing applicable post/zip codes based on county selected in list 1 and finally list 3 opens in another new frame giving quantity options. And based on the choices selected in each dropdown list, a new page opens detailing the cheapest suppliers in ascending order for the applicable quantity in the customers area. How would you go about doing this?

I'm pretty new to php and mysql but i've got a lot of time on my hands and any advice would be greatly appreciated.

Regards... Sparatacus

learning php+AJAX+JavaScript )
with AJAX you load php script, which make chooses and return result to JavaScript.
with JavaScript you make other manipulations.
simple example:

function LoadPageCountry(...)
<select onchange="LoadPageCountry">