I actually do quite a bit of mailing. I enter sweepstakes and what-not and still have bills I can't pay online, because at some point the vendor just went eh...technology, and opted out of the 21st century and so forth. Anyway, one of the things I really use too many of is postcards. They mail cheaper than letters and sometimes, they're necessary, shiny, little evils.
I order custom ones through Vistaprint. They allow for some pretty nifty design features and look nice and professional. I use the ones I send out for sweepstakes to hock my book, Carpenter Springs, on Amazon. I've received some compliments on my postcard design. I like the price and ease of re-ordering them.
I've actually created another set of postcards to advertise this blog in hopes that someday I'll have more than one reader. *waves*
And supporting the postal service isn't a bad thing. Think of all those postal workers potentially wandering the streets... No one would be safe. No, not even the dog.
Another nifty thing I picked up at Vistaprint is an address stamp, so I almost never have to hand address the return portion of bills and stuff. Save tons of time; looks better than plain labels.