It’s got to be a personal decision. I would feel ok buying online as long as I had played the exact same model already, then you know you like it and if it’s got a repair or 2 it’s not a big deal cause you can get it fixed. If you have a music store where you can try out a few that would be best… unless of course someone is so new that they haven’t even played a sax yet then I would recommend a few of the well-known brands.