In short, a Sport Pilot certificate is one way to become a pilot. A certificate is what you get at the end of training, you may hear it being called a license, but there really isn't a "pilot license". 

A Sport Pilot is able to fly Light Sport Aircraft and meets the requirements set by the FAA to operate an aircraft. The certificate is earned by completing a training program that includes ground training, dual instruction time to learn flight maneuvers and solo flight time to learn cross-country and single pilot techniques. We recommend budgeting ~$7,500 to complete your sport pilot rating, depending on frequency of flying and readiness for lessons. We estimate the following: 30 hours of dual training, 10 hours of solo time, and 20 hours of ground.