If this will be your only computer avoid a netbook.
Its too limited (small, slow etc.)
This is slightly above $300 but it might be better
If a laptop is around $300 including Windows then the manufacturer will have to to make compromises to save money somewhere. this means that battery live won't be brilliant, it will come with a fan that makes noise, it will run hot etc.
You might actually get a better device buying a used/refurbished model.
I don't know if Amazon in the US has the same policy as in Germany. Here one can return a product 14 days after purchase. Then Amazon checks it thoroughly, repackages it and sells it used on the marketplace.
Sometimes one can make a pretty good deal (got a lense for my DSLR that way, saved me a quarter of the original price ...)
Ah, here you go: