Perhaps if you are going to send some cards, but not all, you should be sure to send them early, so that those who are trying to conserve their finances will have yoyr return address there, and can wait a bit and decide.

I want everyone's address, but will promise to be happy no matter how many or few I get in return. (It'd be too much hassle to keep track otherwise anyway!) A hand-scrawled postcard is cheaper to buy and mail even than a regular Christmas card, so that could be another option for folks!