Ok, for $300 you can't get a dinner jacket made. Much less purchase a full tux. You're going to want to rent it. And if you just want to blend in, get a something like I mentioned you shouldn't (black on black on black) or any other ridiculous "tux" ensemble. It's high school prom, dude. Go wear some stupid orange suit or something; it's like the last time it will ever be acceptable.