I am getting ready to send my postcards off to the printer right now. I am going to send them out via USPS EDDM-retail. If you're not familiar with this service, you should look into it. You can pick which zip code, post office, and route # you want the postcards to go to. I am targeting a couple different routes in two zip codes that are the demographic I am looking for. All newer developments, lots over 1/4 acre, and within 5 miles of home. After its all said and done, I will have 2100 8x6.5 full color postcards sent out for roughly $500.
With the EDDM-retail, no permits are needed. You can mail upto 5000 pieces a day. You bundle them and put a cover sheet on the bundle to show which route it is for and drop it off at the post office of the route you want it sent to. They will then put your pieces in every persons mail box on that route. The cost for the mailing is around $0.17/each. You can send very large post cards out for this rate also, over a full page and the its the same price.
I know this has been discussed here, but its to be quickly forgotten. So again, here is the link... (click on the "retail" tab)