Be aware that Amazing Deals Online is not an Authorized Dealer [audio-technica.com].
Last year, I bought the m50s from Amazing Deals Online through Amazon and ended up returning them a few days later. I carefully opened them up to determine whether they were genuine and it turns out they weren't.
My advice is only purchase them from an authorized seller. It'll probably cost an extra 20-30 bucks but at least you won't have to worry about receiving fakes.