The price of first class stamps is going up again. ABC News reports the change comes Sunday with a three cent increase from 46 cents to 49 cents. Sean Hargadon with the US Postal Service says the increase should generate about two billion dollars in additional revenue for the financially strapped agency. The Postal Service reported a net loss of five billion dollars in 2013. In 2012 the agency reported nearly 16 billion in lost revenue.