A license, only guarantees you a certain amount of sells per unit. You can buy it to sell it yea, but the beat isn't officially yours and can be re-sold as a lease or 'exclusives (get to that on the next line) at anytime.
Exclusives, are the ownership of the beat. Meaning you have officially 'bought' the beat and the full rights to it. Meaning unit sells are unlimited and the beat is solely yours, and cannot be re-sold, via Lease OR exclusive.
So if you want the beat to be 'all yours', then buy the exclusive. If you want to buy exclusive rights to the beat your are interested in, then e-mail sales@shadowville.com or call 1-888-43-BEATS (432-3287).