I think Guitar Center sells them in store but you'll probably find a wider selection online. I think the second question comes down to preference and what you feel more comfortable with while studying. For me it's over ear. (Especially helpful when studying in a room with a lot of people so they easily see them and know not to bother you).
http://www.amazon.com/gp/product/B00XZHQAMC?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00 I just purchased these recently, I had some LG Tones I used for working out but I think they got sweat damaged since I be sweating a lot when I'm working out i replaced them once but started messing up again after a while. These are sweatproof n don't fall off easily like the tones imo. And they were just $59
I use the Ath M50 for over ear and some JVC earbuds that I got for $20 to work out and commute. Now I probably woulda bought the Sennheiser Momentums for my over ear.
Take a look at Xiaomi Piston 3 http://www.neowin.net/news/review-o...nes-unbelievable-sound-at-an-unbeatable-price http://theheadphonelist.com/headphone_review/xiaomi-piston-3-in-ear-earphones-review/