With the continue growth of digital currency and online banking across the country, using physical currency is becoming less and less relevant. The penny, in particular, is becoming worthless. I costs on average 2 cents for every penny created as of 2012 (http://www.snopes.com/business/money/pennycost.asp). Rising costs of metals has caused this currency to become too expensive to use, but luckily, eliminating the penny can help our economy.
In Canada, they have already done this. Its estimated that their elimination of their penny will save them $11 Million dollars a year. That doesnt seem like a lot compared to our nation's crippling debt, but its a start.
Rounding up/down on physical purchases (if done right) would allow the penny never to be used again, and could save millions!