How do you make a toy car...out of common house items, and the wheels can't be previously used as wheels for something else?

Water bottles and nails. The caps are wheels, the bottle is the frame. Cut off one side of the bottle. Drive the nails through the caps and into the bottle, then bend them inwards with pliers to make sure that they stay.
Alternatively, use a vertical half of a milk carton for the frame.
If you have a dowel and a saw, you can make wheels from that.

Comment removed by me, forgot that I could still edit my original answer. Passing mods are encouraged to delete this entry.

I was thinking a shoe box. Cut wheels out of other cardboard. Use pins to stick the wheels into the shoe box and bend them over so no one gets poked. Then you can draw on it and color it to make it look like a car.

Lots of things can be used for wheels – buttons, empty spools of thread, bottle caps, CDs (if you’re making a larger size car) Use your imagination and good luck.

Easy. Paper clips for the axles, plastic bottle caps for the wheels, cardboard cereal box for the body. Check out Instructables. People have been doing this project in elementary schools all across the nation for decades.

Google is your friend !

How odd…I was thinking this very same thing!!??