How much will you pay for Google Reader per month?

It's an irrelevant question -- when you work on the scale that Google does and have the data that they can analyze, it's easy to make the business case that it is either a good business product or not worth the time.

It's easy to make a survey and petition and whatnot, but power users are always the minority (the long tail) and do not drive a business alone. Especially one where the engineers supporting any product are paid six-figures a piece and the product is not directly monetized (i.e. you're not paying for it, you're not hosting the data, etc.)