Watch the classified on here and other RC sites too. I have been collecting older kits and have scored quite a few from these sites (including a Gold Edition P-39).  You will pay less than on e-Bay, but you need to move fast. There a few guys who buy older kits on the classified sites, then turn around and sell for more on eBay. They will grab any good deal on old TF, Royal, Nosen, or other discontinued kit that pops up, so you have to be prepared to jump when something you want appears.

Good luck!
Al