A merchant server of a first merchant receives an indication of items that a customer is to purchase via a web site. The indication may be, for example, a signal indicating that the customer is ready to “check out” his shopping cart of items on the web site. In response, the merchant server provides an offer for a subsidy from a second merchant. The offer is provided before the items are purchased, and thus the offer is not provided unless and until the customer has manifested an intent to make a purchase from the first merchant. A response is received from the customer. If the response indicates acceptance of the offer, then the subsidy is applied to the items purchased. For example, the total price paid for the items may be reduced, or the items may even be provided to the customer without charge. In exchange, the customer agrees to participate in a transaction with the second merchant. For example, the customer may be required to switch service providers (e.g. long distance telephone service) or initiate a new service agreement (e.g. sign up for a credit card account).