Android tablets are generally good for "consuming content" like reading / watching videos, however, they are not really good at creating content / doing homework.
$300 is rather low for anything larger than a 7" or 8" tablet unless you are considering used / refurbished tablets.
The recent release of Intel's Bay Trail generation Atom processor has also meant the release of new 8" Windows 8.1 tablets for $300 or less due to holiday sales. One seemingly popular Windows 8 tablet is the Dell Venue 8 Pro. This the full version of Windows 8, not a cut down version of like Windows RT. Additionally, all Windows 8 tablet should come with a free product for the Home / Student version of MS Office 2013.
At it's core, these Windows 8 tablets...