Why a one time price? I thought at least EC2 made it possible to charge e.g. A few cts/hr, which I would guess would both get you more clients and more money th

Why a one time price? I thought at least EC2 made it possible to charge e.g. A few cts/hr, which I would guess would both get you more clients and more money then a one time fee, as the barrier to entry is lower. I wouldn't buy wowza server, but have one running for 2 years now.