Also, some venues box office is operated by ticket master and you still get hit with the fee. I had that happen to me years a go. I haven't tried buying tickets in person in a long long time, but I'd imagine this is still a thing where you can buy them in person.
In the Bay Area, you can't even guarantee tickets at the box office! They start the sale online BEFORE the box office opens so when you show up, the show might have already sold out!
Here's what the website for my local big venue says:
"Please note the TD Garden Box Office does not sell tickets at the public on sale. All tickets should be purchased via www.ticketmaster.com"