It amazes me how many people in 2013 are falling all over each other to get their hands on low-powered, highly-directional, in poor technical condition, mediocre-coverage AMs...on the radio band that less than 20% of radio listeners even tune to.
Even with great programming...unless there's enough advertising dollars every month and a minimal weekly cume audience that shops those advertisers (so they keep advertising!)...most of these AMs won't earn enough money to pay the electricity, bank payment, and rent on the studios...not to mention any employees salaries.
And, no...no matter how great the station sounds...these type of AMs rarely get any kind of ratings. Ratings in smaller markets don't drive significant ad revenues anyway.
Sorry to be depressing...but, my opinion is don't waste your money on a terrestrial radio station..especially an AM, unless you are wealthy and can afford to operate with a total lack of any income for several years...or you plan to run the station as a non-commercial, no-profit/hobby.
Why not create an internet/streaming radio station as a test? Doing so costs a tiny fraction of even buying a small AM station.
Try to build an audience by promoting locally through social media (mostly free) and other free or bartered sources...and after website analytics proves your web station has an audience in your area...hire a couple sales people to generate some income (or sell ads on your station yourself).