Those aren't stamps, but Christmas Seals, issued by the American Lung Association (or their predecessors). The Christmas Seals you have seem to be from the 1930's, so a list of them can be found at this link:
http://www.christmasseals.org/galle...30-1939.htmlAs far as values are concerned, they are listed in the Scott Specialized Catalog of US Stamps with the prefix "WX" but most of the ones from the 1920's forward have a very nominal value listed at catalog minimum of 20 cents. Typically, you'd have to go back to the 1900's or 1910's to find Christmas Seals valued at more than a few cents.
Putting values aside, they are pretty easy to collect, are very colorful and will make a nice addition to any stamp album or stock book.