That problem could be easily solved by a simple business agreement and almost no new software at all. That solution is the common
Yes, the kind you buy in Wal-Mart for $20 for 350 minutes.
All that needs be done is to get AT&T and/or others to agree to debit monies from their phone cards for purchases on the Web.
Like this ...
When you want to buy something small or make an "entry fee", game fee, or some such thing, you type in all those zillion numbers and ... wait a minute ... you type all the numbers one time into a text file - then cut & paste them into the browser form field and ... Voila! You're in!
If done with these cards, you'd also only be risking $10 - $50 at any given time. If someone "got" your number you'd only be out those bucks. Just get another card. And ... you can get these cards just about anywhere even at 7-11 or Krogers.
Since the payment is certain there's no hassle. It's good as cash ... and ... it's already in place. All that's necessary is "an agreement".
Later, when the practice is established, others will get in the act and Microsoft & Netscape & Opera will make a special holding pen for these numbers in your browser. Then you freeloaders are gonna' pay me 1 cent per pageview ...