I'm going to charge a rapper for a beat after giving one for free
Does the rapper not want to pay for the new one?
Yes, he thinks my beat is not worth anything.
If I were you, I would have given the pricing for my content before I gave any freebies so that there will not be any misunderstanding. Some people do not know that what you're doing requires work and costs money, so it's better for you to outright tell them what you're worth.
Are you sure I should do that?
You should always get paid for your work. You put in time for that, and you're worth it.