Hi there Mike!
If he is worried about the little bit it would cost for a cashiers check, tell him you will knock $5 off the price of the car!
Or better yet. As mentioned above, tell the guy to send a US Postal Money Order. They are only .90 or $1.00.
They are guaranteed, and tell him you will knock a dollar off the price of the car.
Thats what I would do. Postal MO.
Darren