Cybergold allows you to earn, and spend, money online. CyberSource offer real-time credit card processing and other electronic commerce services. DebitNet DigiGold Digital Silk Road is a proposed payment system for extremely low cost activities such as delivering and routing packets. Downtown Anywhere has a system using account numbers, and personal payment passwords. Ecash is a fully anonymous electronic cash system, using Chaum's blind signatures.
Free tokens are currently available.
There is a further extension to allow small payments, which are aggregated as a single SET transaction. Value can also be transferred to another account holder. More research can be found here . New Notions and Techniques, by Yiannis Tsiounis. Electronic Funds Clearinghouse provide payment transmission and intake conduits over the Internet.