Here's a web link for craftsman lawn mowers. Just follow the directions as indicated. The first step is to enter the first three digits of the model number, so I can't hepl you any further than this: good luck
I don't know how old that model is, but if you go to sears.com there are photos of all the lawn mowers that are currently for sale. Lawn and garden section. Otherwise try EBAY they have lots of lawn mowers and you can narrow down what you're looking ...
check your local classifieds; check with a dealer who takes trade-ins. Check with an on-line site such as Craigslist or the auction sites for completed sales.