While there are some android 7 inch tablets the quality is too low to consider today.
I have the Nook Color with an upgrade to full android but it missed your price.
I have yet to see the newer nook black and white. Read a review and see what it can do along with the Kindle.
I'm a graduate student, and frequently my classes disperse reading materials that the professors have put together in pdf or other formats, often around 50 pages or more. I need something that I can connect directly to my computer (where I've received the professor's email containing the materials) and transfer pdf files (and preferably other files like Word, but definitely pdf) directly to the reader. I'm also on a budget, and would prefer to spend in the $100-150 range. Any advice about what the best choice is to meet the above specifications is greatly appreciated. Thank you!