I'm currently working on a site that makes several calls to big name online sellers like eBay and Amazon to fetch prices for certain items. The issue is, currently it takes a few seconds (as far as I can tell, this time is from making the calls) to load the results, which I'd like to be more instant (~10 seconds is too much in my opinion). 
I've already cached other information that I need to fetch, but that information is static. Is there a way that I can cache the prices but update them only when needed? The code is in Python and I store info in a mySQL database.
I was thinking of somehow using chron or something along that lines to update it every so often, but it would be nice if there was a simpler and less intense approach to this problem.
Thanks!
How are you getting the price?  If you are scrapping the data from the normal HTML page using a tool such as BeautifulSoup, that may be slowing down the round-trip time.  In this case, it might help to compute a fast checksum (such as MD5) from the page to see if it has changed, before parsing it.  If you are using a API which gives a short XML version of the price, this is probably not an issue.
Caching online prices fetched via API unless they change