sell the pennies and pay the fee once is on bitcoin.. easy way...
The problem is the transfer out of the exchange takes a fee (from the currency being withdrawn). If you are a new user and only have pennies there is not a way to take a percentage of a whole coin. The way to get it on the exchange would be to simply wave the fees entirely. But that would be charity, and the only businesses that can run on that business plan don't last.
The withdrawal fee would most likely be a flat amount (like every other currency on every exchange). If it's .05 pennies or whatever, just be smart enough as a trader to have a balance of xxx.05 or so (to minimize what you'd have to leave on the exchange or trade for another currency to withdrawal).
As I mentioned above, pennies are completely divisible on exchanges. No reason to worry about whole numbers when it's traded. (again, unless I'm totally missing something....)