common is too short to hay and doesn't produce as much as coastal.
Native grasses are not a replacement for coastal. Sure you aint gotta fertilize native grasses but they don't produce for squat. you can run a cow/calf on 3 acres or less of coastal with native you are talking 10-20 acres or more. now if you have a 1000 acre west texas ranch I guess native is ok but most don't. lots of grasses to choose from but the improved varieties of bermuda, coastal, Tifton, Midland, Brazos are all good choices.
If you don't plan on fertilizing the coastal or other improved varities then don't waste your money planting them.Just buy some cheap common and maybe a giant variety and plant that.