gotprint.net is one of the least expensive printing services I have found for postcards, flyers,doorhangers and business cards. They offer mailing and addressing, but thier main gig is cheap printing. You can get full color both sides 4x6 postcards for about 2.3 cents apiece if you buy 10,000 ( or 230 bucks) 6x9's, the ones I like, and are the same price to mail and address as 4x6, are 7.2 cents each for 10000. UV coated, color both sides, 14pt paper. good stuff.