I have developed a software. There is a client who wants to buy full rights of it. He will make me one time initial payment. I will give him the software with full source code and other related documents. After that he can do with the software whatever he likes. He can modify if he wants. He can sell it at whatever price he likes in his name. He can even claim the software to be his own. He will pay me only once initially. After that he does not need to pay me anything.
Without any modification, the client can easily sell one copy of the software in 350 USD. He wants me to quote a price for selling full rights. I do not know how much to quote.
Any idea what things I should keep in mind to decide upon a price?