I'm no marketing guy so please excuse what may be some naive questions prompted by his how-to-pay page. I gather that tiered pricing is considered good practice

I'm no marketing guy so please excuse what may be some naive questions prompted by his how-to-pay page. I gather that tiered pricing is considered good practice, but how effective is it to use a jokey, edgy and possibly sarcastic or insulting tone when explaining the rationale? Does it not undermine his professional credibility, or is there some new trend in this area that I'm unaware of? Is it a good idea to tell people how much to pay based on how much you think they should be able to afford, or is it better to let them decide for themselves with just a little subtle help? I'm thinking of how Apple sells iDevices at several price points separated by big increments for small increases in memory rather than directly asking people how rich they are. On a related note, if you were in charge of a budget for acquiring books on behalf of an organization, would you be able to justify spending any of it on a web published book like this one with no hard copy? Would it raise any eyebrows to opt for a higher price tier with exactly the same offering as a lower one?