There is a Marchon guide which was put out a few years ago that lists 99.9% of all the known Marchon cars. These two cars came in a few variations, but are not rare. Some variations were set only.
Most Marchon cars came in sets or (I believe) via mail order. There were very few packaged Marchon cars.
Those Marchon cars, in perfect condition, would probably be between $18 and $20; and then probably only from a collector. In used condition, maybe $10.
You can find some really well running Marchon chassis. You may find that even though some chassis look alike, some have much stronger traction magnets than others.
Marchon quality control was not very good. A lot of brand new bodies may look used, or look like they were done by someone in a rudimentary art class. But they are still be fun.
You may find they have a longer guide pin than most cars, so be careful if you take them to other types of tracks. Also be careful with the body clips on the red one. I have a few where the inside tabs break off fairly easily.
Joe