How can I obtain about 1 oz of paint for wall scrapes?

Unfortunately no, but you can buy sample sizes (some people call them test sizes), which are a little bigger, but still much less than paying for a quart of paint. I prefer to have leftover paint, you never know . . .

Try some acrylic craft paint from Michael's or another craft store. It comes in every color you can imagine, costs about one dollar, and cleans up with water. Dries super-fast,too.

Some brands have paint samples for $3-5. Then you can buy pint cans of paint but will have to tint yourself as they only tint quarts and up.

Go to Home Depot, they have sample paints.

Walmart carries samples

Ty

Joanna has a really good answer-the paint in the tube will be thick so just ad a little water-use your finger to cover the marks