Selling my car-
Once I get the offer and both agreed. How
am I going to get paid?
You meet up with the buyer and he pays you. You then give him the signed title and the car keys. That's it.
If you want someone to do all the paperwork you can try the services of AutoPay. From what I have seen here people are very unhappy with all the delays and confusion associated with having an intermediary in their car sale.