Here is an idea that can save you money, show you care about the environment and support the post office all at one time.  It is a very simple idea.  First save the Christmas cards (Holiday cards for the PC) you receive this year.

Cut off the front covers.

If there is no writing on the back of the cover, as is often the case cut them down to postcard size.

Resend them next year as your holiday cards.  Postage on a postcard under 6″ X 4.25″ is only $0.27 (vs $.042).  You will save money, be green and the planet will be greener.  You can get the self-righteous glow without the cost of the Prius.

it works for the sparkly ones

And you can make a mated pair out of the big covers.