You're staying away from games due to "fan violence"? Unless you're planning to see the Eagles in the old Vet in the late 1980s, I think you're pretty safe. I got to a bunch of football and baseball games every year and I've never had a problem. I've seen a random fight or two over the years, but security is usually all over people. I've never felt threatened at any sporting event I've ever been to.
Cost is a bit of a more legitimate reason. When I go to football games, I'm just paying for me so it's not too bad. For baseball, I rely on Stub Hub. This past August I took the family to a Mets - Phillies game on a beautiful Thursday afternoon. We had great seats and with parking, tickets and some snacks for the kids, I think I paid $130 for the day.