DEA informants are paid anything between $49,746 for a GS-7 and $55,483 for a GS-9, when you do not have a lot of experience. As you grow in your career with them, your salary can go up to $92,592, because at this level you are more experienced. To learn more about DEA informants, visit http://www.justice.gov/dea/job/agent/faqs.html.
Informants for the DEA usually are trying to get time knocked off of a future criminal charge. They are usually about to go to prison for a serious crime, and they are trying to get their charges reduced. Most informants are not the kind of people you would want to spend time with.