1928 Coca-Cola Bank of Watertown Checks

These are some of my favorite items, they are Coca-Cola Checks from 1928. They are from the Bank of Watertown, a small town about 45 min out of Nashville, I purchased 6 of these from a friend in Alexandria. In my opinion they are rare because of the fact that the town is so small, but really don't know what they are worth. If you have any info please comment, Thanks.