I would agree with Ascinder. Get into the CV, give it a good cleaning and check to see if anything is marked up. If everything looks good, just repack it with grease and put a new boot on it.
I have been having some issues with my driver side inner CV and have been having a bear of a time finding a replacement axle. The outer axle (from the inner CV to the wheel) is relatively easy to find and EMPI makes a replacement that you can get for $70. The part number is 80-3619 ( http://www.jcwhitney.com/new-fwd-dri...41&zmap=548592 ) and they are super easy to find. Triathlete has replaced his axles with these and says that he hasn't had any problems with them so far.
If you are looking to replace the whole axle all the way in to the third member let me know because that's what I have been up against, and with the help of a few members here I have finally pulled all of the part numbers together to get that done.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless