At a speech in Delaware Monday, Gingrich supporters were offered a chance to pose with the former Georgia congressman, but only after the fee was paid.
"We are trying a new tactic and asking our supporters at rallies for a nominal donation, and guess what, it's working," a spokesman told the weekly magazine National Journal in an e-mail.
The publication referred to the Gingrich cash-raising tool as "a sign that his campaign is in need of fresh funds," and pointed out the candidate reported more debt than cash at the end of February. Gingrich has won just two primaries -- South Carolina and Georgia.
Those lining up to pose at a rally in northern Delaware Monday evening were told they could find their photos on a Gingrich Web site, after they provided the campaign with credit card information.