I think that the below calculation are not realistic. One of the most important things in calling cards is the ability to market the cards,and distribution (depending on what area you are focusin ) The margins are low and you will need $$$ to make it profitable and live by it. There is market for it, but one has to really know it.
Big players in big markets tend to swallow the small ones and corner them with offering and promotions. It is a tough market.
that is just my 0.02 cents.
take care guys…