Not even a whole tux, just a tux jacket. I only need it for 1 night and only for a few hours. That's why I don't want to spend a bunch of money. Any ideas? I'm in Houston, in case you didn't know.
I'd go with rent one. However, if you feel you must purchase it, you may want to try a resale shop in a ritzy area (River Oaks-ish).
I traded an old recliner for a vintage '40's tux several years ago. A friend of mine was into costumes (he did some acting, and has an amazing collection of fedoras I'm terribly jealous of, now that I have very little hair on my head), and got one in a deal that was too big for him. That's one of the best deals I've ever managed. The chair was a piece of junk. Good luck!