Depends on the market probably, but a lot of spots it’s like $50-$100 extra, each way, to upgrade to the seat level that let’s you choose a seat. Frontier and spirit used to be the joke, but most of them are doing it now. Cliche joke used to be that they’d charge you each time you used the bathroom (maybe they actually happened in Europe, Ryanair?) But like too many things, we’re close to living the onion.