I'm not going to give out free rides
What is your reason for not wanting to give out the free rides?
They'll only be free to my friends
It is your right to refuse service if someone wants it free. You need to make a living too, so you need to charge money whenever necessary. Sometimes being too kind is a bane.
Oh of course. I'm going to teach everyone that wants a free ride a lesson.
This is fine to not offer the free rides, however trying to teach them a lesson may be too much. Just let them know that they have to pay and if they cannot, then turn them away for other paying customers.