Susan Headley, author of the 'Guide to Coins' on About.com, is a lifetime coin collector who has been boosting her income by searching through circulating coinage for the past six years. In 2008, she made about $2,500 and so far in 2009, she has earned approximately $500 from coins she's found.
People who search circulating coinage successfully for a side income do so in very large numbers, she says. They buy rolls of coins from banks, typically in whole boxes, and sort through it to find stuff that just doesn't belong, Headley says. Half dollars, for example, were no longer made from 90 percent silver after 1965, but they still had 40 percent silver in them until 1970; either of these turn a nice profit. Presidential dollar errors can be worth $50 to $5,000 each; uncirculated state quarters can sell from $10 to $50 per roll; and rare error coins can value up to $35,000.
