This is a FAQ: for your first sale, you sacrifice the price (all the way down to free if you have to). For the next sales, you show your reference customer.
Free is not a sale. You have to charge something to claim them as a customer.
You know what I mean. Even in EDA, having a reference "user", as long as they are using the product, is a major achievement that will be leveraged [to death] with future [paying] customers.
I am not trying to be pedantic. In my experience there is an enormous difference between having a user and having a paying customer. They may be a user before they are a paying customer, but there is a very significant difference.
But you don't have to tell that you first customer doesn't pay you ;).