Find areas to farm and send postcards via the USPS's Every Door Direct Mail (EDDM). 

So as I am learning about shotgun marketing I am hearing that the process in general could be quite expensive yet no one has explained specifically what parts of the shotgun style of marketing actually IS expensive.Besides the cost of stamps, post cards and envelopes, (and I'm told I also need to purchase a $150 permit from the US postal service in order to send bulk mail) what other expenses do I need to take into consideration?

Once the website is built now I need to get traffic there, I plan on sending out postcards and/or yellow letters out to every single family home in one town.- what is the most efficient way of doing this?

Use yellow letters, post cards, driving for dollars, bandit signs, etc.

There is no magic new strategy for finding sellers, it's about assessing data and processing it, getting good contact info or sending compelling, not sleazy postcards.

Im doing some marketing via postcards to a abseentee owners list as well as older home owners some of my postcards have come back any ideas on what to do with the return mail?

Then drop the notes, postcards, etc in the same time frame.

However, I have heard that using yellow letters or some of the postcard services out there produce great results as well.Any suggestions?

I get a lot of postcards. 

.- Print campaign - initially with a jumbo postcard (unique size 12x6 to catch attention).