My sister bought a laptop on sale from walmart that competed in price with most netbooks. Just under $200.
Honestly, there's little that you can't do with a laptop/netbook that you can do with a desktop. I stay away from them personally for the following reasons:
a) less serviceable
b) can't custom-build them (I can't at least)
c) no need for mobility
If you're like me and dirt poor, I'd just as well buy the cheapest thing you can find. Make sure if you put linux on it maybe dd an image of whatever came on the laptop for safe-keeping. A lot of the cost of laptops/netbooks must come from licensing Windows (I think), so even if you prefer Linux there's no sense in throwing away something that you payed for.
Protip: look into imaging the os that comes on the laptop and adding it as a virtual machine under Virtualbox (or something analogous) under Linux!
"I'm going to get into your sister. I'm going to get my hands on your daughter."