The seed is pretty expensive...about $12 per pound. However, you only seed it at 2-3 pounds per 1000 square feet versus about 8 pounds per 1000 square feet for fescue. Also, don't apply any fertilizer....it will make other things grow faster than the buffalo. Finally, only till your area about an inch or so deep. Once you broadcast the seed, lightly drag a rake over it to scatter a bit of dirt over the seed and then pack the crap out of it either with a riding lawn mower, a roller, or your feet. You will still see seed on the surface and that's OK. Buffalo likes intimate seed to soil contact which the packing provides. Water the hell out of it until it gets tall enough to mow and then you should be good to let mother nature take care of the water after that. It will take a while to get it established and totally fill your area in, but once it does you will be golden.