Think of it this way, we have Construct 2 and we are selling licenses for it. Because Construct 2 is in Beta we are rewarding people who buy it now as early adopters by giving them a significant discount. Once you buy a license you have a fully licensed copy of Construct 2.
Any new builds of Construct 2 are compatible with your license. You would only need to pay when we release Construct 3 which is far, far off in the future :) We release new builds all the time.
