Abstract: A third-party billing system and method permits consumers to conduct e-commerce transactions (including microtransactions) securely and anonymously by providing billing and personal information to the third party billing system rather than to merchants. A consumer initiates a transaction by placing an order for a product. The consumer then authorizes the transaction by transmitting an authorization code to a billing computer. The authorization code identifies the consumer billing account to which the transaction is to be charged. The authorization code can also authenticate the consumer through use of a PIN. Multiple consumers can charge transactions to one billing account, in which case each consumer can be assigned a different PIN with restrictions that limit that consumer's use of the account. The billing computer then verifies the authorization code and transmits an approval code to the merchant computer.