Create a list of potential features and provide each with a price. Just like for a real product, the price can be based on development costs, customer value, or something else. Although the price can be the actual cost you intend to charge for the feature, this is usually not required. Customers buy features that they want in the next release of your product using play money you give them. Make certain that some features are priced high enough that no one customer can buy them. Encourage customers to pool their money to buy especially important and/or expensive features. This will help motivate negotiations between customers as to which features are most important.
This game works best with four to seven customers in a group, so that you can create more opportunities for customers to pool their money through negotiating. Unlike the Product Box game, the Buy a Feature game is based on the list of features that are likely to be in your development road map.