John Gruber, reflecting on the New York Times’s subscription pricing:
The decision to purchase and the act of paying are part of the experience for any product or service, and should be designed accordingly.
Not paying is always simple.
Make purchasing something easy, simple, and understandable. Help me figure out exactly what I’m paying for and how much it’s going to cost me over a specific amount of time (or forever). If you can’t do that, I’m probably not going to give you my money unless it’s something I’ve decided I can’t live without.