For existing Gunbot owners who have licensed a particular exchange and want to switch to another exchange. For example, maybe you bought Gunbot and licensed Bittrex, but later decided you want to use Binance instead.
Also, if an existing Gunbot user has lost their API key or secret, and needs to re-generate their key and get a new one activated, this is the cost to perform that action. To prevent this fee, it is highly recommended that users generate a master key and get it activated, and then use a second, different key for Gunbot use. GBU offers guides on how to generate keys for the different exchanges, along with tips and warnings on how not to lose them.
If you buy your API swap from Gunbot University, you get a free month of GBU Associate membership.