Vegas Baby! (hopefully)

Next weekend I'll be off to Vegas for my coworker's bachelor party. We'll be there causing havoc, breaking hearts, indulging in an excess of booze, gambling, and strippers! We're staying at the excalibur because that's the cheapest hotel room on the main strip, which unfortunately isn't very cheap that weekend. We all have our own rooms because, well, frankly we don't know each other that well, or maybe we do know each other well enough to know to get our own rooms. I booked my flight on us airways, but the website was having major issues when I booked it. Web pages would constantly error out. I finally made it to select my flights and seats, entered my credit card in, hit the final submit button, and then I got a web page timeout! Nooo! There were only 3 seats left on the same flight that a couple of my coworkers had already booked. 5 minutes after desperately trying to get back in the website, I get a email telling me my ticket has been booked succesfully. It had a ticket # seat number and everything. I look down at the purchase price and it said $0.00!
Uhoh, what the heck just happened? The next day I call up the airlines and asked to see if everything was ok with my ticket. I even told them the website was acting all funky and the amount I got charged was $0.00, but the ticket person said everything looked fine, then thanked me and to have a nice day. While I'm all for getting something for free, I'm really afraid that I'll show up at the gate, and they'll say that my ticket is no good, and the flight is full and if wanted to go to vegas, I would have to pay full price. So I'm crossing my fingers and hope everything goes ok with the ticket.

*update* I just checked my credit card activity, and they did indeed charge my credit card correctly. Looks like no free plane ride for me.