When registering, X gave the professional 10 CREDITS, so that the first ten clients found through X are free.
-Android: application accepted by the client, the trader will accumulate a "debt" to Pitagor4 of 1 €. The server will disable temporarily sending new requests from customers where the trader exceeds a number equal to 20 debts are not welded. You can pay off the debt from time to time (that is, each customer acquired after the twentieth) in the restricted area of the site https://my.X.com, or "prepay" new customers to stay below 20 debts. At the time of registration, X gave the 10 professional CREDITS, so that the first ten clients found through X are free.