incrediBILL - 9:18 pm on Oct 13, 2012 (gmt 0)

I would run the API on a cron job and cache the results, I think Amazon allows 24 hour price caching, because doing it in real time just slows the site down to unreasonably slow speeds. Google doesn't like slow sites and dings those that don't load as fast so you definitely don't want to put anything in the site that will inhibit page performance.