Depends on her desired riding position, her size, and how much she'll practice.
Riders don't need to be able to put both feet down at a stop, but if they can't it requires additional practice and confidence.
For sportbikes/nakeds/standards basically anything 500cc and under is a good starter bike. Ninja 250/500, Hyosung 250, Rebel, Buell Blast and any others.
For Cruisers, it's not too much of a problem to go higher cc such as 650 as they don't bolt like sport bikes. But weight still matters, as it's good to learn on a smaller bike.
Have her sit on various bikes to find a riding position she likes.
There's a forum for beginner bikers you can check out.
HereTake heed of recommendations and answers from that site.
ETA: Since you mention she's on a tight budget, don't forget about Insurance and Protective Gear. Insurance is pretty low on smaller CC bikes so not too much of a problem. Helmet, gloves, boots, jacket and pants can be another story. Check out ADVrider.com's Equipment section on good advice on gear. If you can't afford the best, something is still better than nothing.