Or brochures and business cards.  I've been using Custom Postcards Direct for many years now.  They are located in Pennsylvania and you can find them online at www.custompostcards.com.

They offer 4-color both sides business cards and postcards, and their prices are very good(at least I think they are!), and the service is excellent.

For example, when I get a really nice listing in a walkable neighborhood I will order 5,000 color postcards.  For this, I usually just get one-sided color postcards, which cost just $179.00 plus shipping for 5,000 pieces.  Then I give a bunch to my client, send a bunch out to all the neighboring brokerages, walk the neighborhoods and leave the postcards at coffee shops, CD stores or wherever they will allow you to leave postcards or place them on bulletin boards.  They look professional, and clients love the fact that I take this extra step.

Now that listings are on the market for months at a time, since I have 5,000 postcards I can send one out every month if I want...and when they sell, I can slap a "SOLD" stamp or sticker on it and send it out again. 

I, and other agents in my office, also use them for personal mass marketing.  The only thing is, you need to submit the postcard design in a certain format, which unfortunately I know nothing about since my husband does it for me(he's in graphic design).  And it's best to get it right the first time, or you'll get charged hourly graphic design fees. If you have a designer friend it would be great to barter for service!

Anyway, check it out for yourself! www.custompostcards.com.