It may or may not work buying her the ticket depending on your motivation. If you think buying it for her will make her want you, you will fail. If you get her the ticket and make no mention of it you'll be fine. If she finds out somehow it was $100 act like it was no big deal.
Theres always the debate on who should buy what. It doesn't matter. If she likes you shes knows it right away, if not buying her dinner and drinks will make no difference. If you buy a girl something with the intentions of 'please like me' she will see it from across the room that your desperate and weak. If you buy a girl a drink cuz you dont care and you were going up to the bar anyways she'll think your a decent guy who isnt trying to impress her.