There are a wide variety of opportunities for Gap years:
Planning to attend college? You should still apply and then work with your college to request an admissions deferral.
Benefits can vary depending on the AmeriCorp program, some provide health insurance, stipends and cover travel expenses. Most provide scholarships towards college upon completion.
These are just a few of the organizations that offer service programs for young adults. Before doing any program make sure you thoroughly research it by talking to alumni and program representatives and understand the costs and benefits.