I spray about 50 acres per round. Liquid Pre-emerge cost $835. Granular $2500. That is for bermuda treated with barricade in Feb and April. Those #'s are approximate (per round), but you get the idea. WG is even cheaper. If you pre is done right, your need for post should be limited and can probably be handled with a back pack. Save your money and start spraying.
The reigning Mayor of Stupidville