When the netbook craze began (2008), I bought a 9" Acer Aspire One, for roughly US$400. That was my main laptop (and, during vacations, my main computer. Yes, I work at a university, so six weeks of vacations every year).
One year ago, I decided it was time to renew. I bought its sucessor, the 10" Acer Aspire One. For US$350. And it's my main computer outside of my office. I am really happy with it.
I have just bumped up its memory (2GB6GB). Besides that, I'm more than satisfied with what I got. I have recommended it to my family — Nowadays, my wife has one, and I have taken three more to her family (mother and two brothers). We are all quite happy with them (except for the sister that insisted on keeping Windows 8).
So, yes, US$400 for a good five year use... Is about US$80 per year. Quite acceptable!