I talked with Scott, with scottshelicopter.com

He was thinking around $17-19/acre to spread 70 lbs/ acre  (this was for soybeans earlier this spring, but should be the same for fertilizer) .  He said that it depended on product, but could go up to 80' swath, doubt it would be quite that much with urea.    Might be a little more expense with smaller irregular shaped fields.