This cycle is truly messing with my head lol. Right now I have 2 interviews one for my top school but I don't feel comfortable putting all my eggs in one basket. The other school I have an interview for is overwhelmingly expensive. I'm realizing now I should have added more OOS friendly publics to my list. But thanks for the reassurance!
I'm also interested in any input on this question. Did you end up adding anymore schools to your list and which ones? I was thinking about adding Louisville as it seems OOS friendly, but i'm just not sure on the timeliness since it is getting late into the cycle.
If it makes you feel better, go for it. It's only a few hundred bucks, and if it gives you peace of mind, might as well. At this point, you'll probably only be getting post-December interviews. I'd wait until after December 1st (or whenever acceptance day is this year) to buy any plane tickets, though, since you may get in to your top choice and not need to go.