I pretty much live in two places and want to get a cheap laptop for web work.
Basicallly I’m too lazy to even carry my 13inch macbook around! So looking for a portable laptop.
Macbook Air is too expensive. iPad would be ideal but given the closed Apple Store, I guess there won’t be any chance of getting a local web server running on there.
Is the small screen a big limiting factor? Are there netbooks with fairly high resolutions?
If you want something in that price bracket, look towards the Netbook range, their the cheapest kind of machines but they can be really good for portability as their less heavy (usually) and being lower specification means you’ll get a decent battery life at a reduced price. The only issue I would say is if you need to use products like those made by Adobe as they have seriously high system requirements and you wouldn’t be able to get away with a low spec machine. If you just use a general purpose editor and a few basic products (like Notepad++ or one of the less bloated coding environments), it won’t be an issue though. 
But I guess they are quite expensive?
My budget is like $400.
Not sure you really need power for web dev?
you can buy one of those small gaming machines, they should be powerful yet light weight.