Tacoma Narrows?

My friend is training for the Tacoma Narrows Half-Marathon that takes place August 1st. I've run with her a few times and while she is out of town for the next two weeks, I'm running with her running partner. It's pretty exciting. We ran about 6 miles on Thursday and then closer to 7 on Saturday. They are trying to convince me to run the half-marathon with them, but I'm struggling with the concept of paying $75 to run 13.1 miles. I may end up running it with them, but not registering for the race and thus not receiving a t-shirt. That's okay with me. The training workouts have been great. Doing 5 miles tomorrow at 6am. I'm starting to prefer distance running... maybe I've lost my mind, but at least I've found a new hobbie!