I made a similar page that gathered prices from different book vendors based on ISBN-AEN numbers. I created a vendor-specific RegEx to retrieve the price values after looking up the book page via GET-query on the address bar. This approach required PERL (at the time), now I would use PHP...and simply build the results page on-the-fly before sending it off from the server to the client-browser.

So if I had to do the same thing but gathering the price values from XML I would probably still grab the latest values on-the-fly and definitely use PHP's built in XML parsing functions to make this pretty easy.

1. Client Request for product
2. PHP grab XML and extract values from same
3. Build results page & publish to client

Hope this helps.

Thanks for your help..
I initially thought about going this way but I'm pretty sure it would be to slow to function well..
I'm using quite a few xmls so grabbing each one of them realtime on page load sounds a bit tedious and really not efficient server wise.
How did it work for you with the ISBN-AEN numbers? acceptable loading times?