here are some cars I built some time ago. they are all coffee Stir Sticks from a burger joint.
I used different methods, from tea to alcohol and shoe polish. The key was to experiment on
the wood before you actually do the model.
Other things I used where cheap chalk, ground and brushed on and then set with cheap hair spray from the 99C store.
You have to put up with some funny smell for a while, but way cheaper than the craft store stuff.And the same material!
Half the fun is playing around with it. By the way ,the only commercial items on the cars are the trucks and some copper wire.
Merry Christmas and happy messing around