Dallas Fort Worth has always had healthy rates for leasing as well as advertising. At a bare minimum, I'd suspect about $36,000 but with the FM translator proliferation it can drive an AM without a translator down in the actual rate achieved. Rates really vary by market and coverage. I've seen major market rates (larger markets) as low as about $25,000 and as high as $80,000 a month. Amazingly in number of people in the primary listening area is not much different in regard to price. I think this is because a company willing to lease has an amount budgeted and for a station to accept them, the station must live within the client's budget to some extent.