Don't worry, the plans that they have only have 200 min and 250 sms haha.
Though the one thing i should of researched about the Hero is that its slightly slow in terms of the performence part, she might exchange the Hero with something else [14-day exchange policy], i'd probably be able to convince her to get the Desire and they'll probably work something out with no data [price would normally be $199.99 with 3-yr w/o data] keep the $50 gift card or maybe half price it at the same time.
For example, Angry Birds runs surprisingly smooth on the Samsung but choppy on the Hero.
But the one thing about the Hero thats a plus, HTC Sense UI haha.