A service configured to be accessible by two or more parties to a two-sided funds transfer transaction through a computer network (e.g., the Internet) provides functionality for sending a payment request to a target payer or payee who is not yet registered with the service. Depending upon who is initiating the transaction (i.e., a payer or a payee) the payment requests may be received as requests to send payments or requests to collect payments. In the latter case, the service may be further organized to solicit a payment, for example by transmitting an e-mail message to a second party to the funds transfer transaction. When used to collect payments, the service may be further organized to process one or more responses to the above-mentioned solicitations.