What kind of laptop should I get? Looking for Windows, cheap, light?

I need to buy a new laptop and I have no idea where to start. I want a Windows (8.1 probably) that is light enough to carry around university campus all day and has a long battery life to match. Otherwise, the specs don't really matter. I game a bit on Steam and use Chrome, social media, and tonnes of docs/pics/pdfs/music files but not actual hardcore software. I'm also kind of very much broke so the cheaper, the better.

Light with long battery means an UltraBook, so look through those.

Mainstream Windows laptop mfg ratings:
Lenovo is the number one, followed by Asus, HP, Dell, and Samsung.
At the bottom of the pile are, from the bottom up, Sony, Acer/Gateway, and Toshiba.

Purchasing a laptop is a highly personal decision. You need to decide what type of keyboard you want: do you want a full sized keyboard or are you okay with something smaller? Do you like or despise the chicklet keyboards like apple uses? Do you want a backlit keyboard? Do you want a numeric keypad? Do you want a touchpad and/or point stick? Do you want 2 mouse buttons or 3? Do you want them above or below the touchpad? How large a screen: 13"? 14"? 15.6"? 17"? If you are highly mobile, then smaller is lighter. If you don't move around much then bigger means heavier but a much more visible screen. These are all things to ponder which have a significant impact on how happy you are with your laptop experience.