why is it a collectable? they are still being made, its just that people don't know about them that much and are just used to the 1's 5's 10's 20's 50's and 100's. now if you had a 500 or 1,000 dollar bill, now that's a collectable
but they do have a 2013 one if you go to: http://en.wikipedia.org/wiki/United_States_two-dollar_bill this will explain that they are still being minted and you CAN go to the bank and request $2 bills