This is the front of a postcard that I recently had printed and mailed to promote our upcoming Improv on 4.22.05. I shopped the job around to many local printers and mail houses. Simple job 4 color front grayscale back.
Quotes that I received from local print houses ranged from $500 to $900 for printing of 1500 copies. Add to that bulk mailing charges from a local of about $476.
As luck would have it when researching postal regulations for the back side of the postcard (great advice - do this BEFORE you design - and definitely before you print) I found a blog post about modernpostcard.com.
The same job that had local quotes coming in at $1376 - modernpostcard completed and mailed for $576 including a $100 Express Charge. That's just price - the final product was top quality, I always knew down to the hour what status my print project was in, and you can price all your options ahead of time.
Definitely worth a look-see if your doing any direct mail.