Do you have a picture?
Quick note: 1/2" is the cut-off for pee-wee marbles. 5/8" is a standard size marble. Just 1/8" difference can make a big difference in value.
Without a photo, I'd say you need to assume the marbles are worth maybe 5 cents apiece. Some patches could go into the dollars ... some could go for a lot of dollars. But most will be a few cents.