Netbooks are fine for on line surfing but useless to save anything unless you walk around with a pocket full of pen/flash drives or an external DVD drive.
Cheap laptops aren't worth the money as they will be f*cked in a couple of years.
Decent laptop will cost £500 or thereabouts but will have memory, battery life and all the bells and whistles she will ever want. It will also be stolen within a fortnight.
This opinion is my own, it is not humble but is based on experience of buying all three options.