As someone who does internet stuff (including some bulk mail
applications) for a living, this makes me chuckle.

The whole 'penny a message' thing is not technically feasible:
Email is a 'peer to peer' process with no real intermediary to
be 'toll keeper.' If you send me an email, your ISP's email
server talks directly to my company's email server to pass the
message.

In such an environment, who sells the stamps? Who cancels them?
Who keeps the penny?

While the 'bandwidth throttling' thing sounds good in principle,
it doesn't work for legitimate commercial e-mailers. It's led to
all sorts of problems. For example, if my client has 150,000
customers who've said "please send me your monthly catalog of
specials" (and that isn't unusual) chances are about 30000 of
these folks will be at AOL. So, AOL says 'no more than 1000
mails to our clients from one address in an hour' then we either
have to a) resend a gazillion times or b) split our sends up
over multiple IPs to 'fool' the system or c) go through a complicated,
expensive, and fragile 'bonded sender' program which I can tell you
from experience are a really ill-administered racket.

Spammers can rather easily (more easily than many small- to
medium-size businesses) pull off (a) or (b)).

So all throttling programs really do is to hurt legitimate
businesses and deny paying customers receipt of emails which
they've asked for an to which they're entitled delivery of same.

On the other hand, there are very adequate solutions such as:

a) Bayesian filters--- mine are 99.8% accurate in filtering my
   mail, which after more than a decade of public addresses is
   about 95% SPAM.
b) Responsive context-sensitive filters at ISP--- I've recently
   moved my personal email to one which, for example, is quite
   successful at blocking 'image SPAM.'
c) Anti-virus programs which miss very little AVG is free,
   Norton and McAfee are also quite good