Occasionally
Amazon will have a good deal on a stamp catalogue but not very often.
In general
ebay is not a good place for catalogue bargains. The prices individuals are asking for Michel catalogues are ridiculous. $25.00 to $50.00 or more for common, 15 to 30 year old, Michel catalogues is insane. And what gets me, the same catalogues stay on
ebay for years at those ridiculously high prices. Doesn't anyone realize that if you have the same item on
ebay to 2 or 3 years and it NEVER sells that maybe, just maybe you're are asking too much?
Personally, I use foreign catalogue like Michel and Stanley gibbons for reference and not prices, so 10 year old catalogues work well for me, provided I can get them for the right price.