gimme cap
n.— «They tell you just before you crouch down for the first time in your little touristo huddle, with your gimme cap tucked in your pocket to keep it from flying away.» —“A helicopter, then a hike: Canada’s five-star wilderness” by Joe Nocera International Herald Tribune (Paris, France) Sept. 10, 2007. (source: Double-Tongued Dictionary)
A ‘Gimme Cap’ is a baseball-style hat given away at an event as a marketing strategy. They are usually embroidered or printed with the name or logo of the event or company. Industries utilizing this strategy range from consumer goods to financial services. Stereotypically you might expect manufacturers of farm equipment, automobile parts, beer, and computer hardware. To manage cost they are often of slightly inferior quality.
e.g. At the state fair: “Be sure to go by the auto showroom–Ford is giving out a really cool lookin’ Gimme Cap.”