I'm just gonna assume here (and I know what that implies!), but she'll probably want something shiny and new, which will severely limit your options in terms of obtaining the most quality for her $$$. You know where I'm going with this ... if it were for me, I'd get a Yamaha F-310 off of CraigsList - I see them all the time for around $100. IMHO, one of the best starter gits out there.
Nekkid Bart: "This is the worst day of my life."
Laffing Homer: "Worst day SO FAR!!"