Pay what you want
Pay what you want is a pricing strategy whereby the customer selects the price they are willing to pay for particular goods or services. This can be as low as zero, or as high as whatever is reasonably feasible. Some adopters of the strategy maintain a minimum floor price, or at least have a recommended base price. Sometimes reminders or nag messages are put in the product to encourage users to either pay more or at all if they enjoy the product. This is a pricing model promoted by services like Itch.io and used by libre games like DUGA. A similar strategy is pay what you can, wherein the seller negotiates a price with the buyer based on their economic means. It is also related to encouraging voluntary donations or tips, as used by creators like Graeme Gott, but with a greater emphasis on an implied obligation to financially support the game's developer if a user enjoys the product.