The first day of issue for this 2 cent red John Adams stamp was June 3, 1938. Your cover was cancelled much later, on November 24, 1938 which was Thanksgiving day that year so it is not a first day cover. Thanksgiving day is the date traditionally used by the American Lung Association to sell their Christmas Seals to raise money for lung disease research. Christmas Seals are not postage stamps and cannot be used to pay for letters to be sent - they are privately pinted labels. They first were printed and sold in 1907 and they are made in different designs every year. For the first several decades all of the money the American Lung Association raised by selling these was put toward finding a cure for tuberculosis. Today the money they take in from the sales of these goes to broader lung disease research such as lung cancer. As for value, a used 2 cent red John Adams stamp sells for about 10 cents on a really good day. A used 1938 Christmas Seal might sell for about the same amount. On a first day of use of the 1938 Christmas Seal cover with the same cachet as on yours there have been two very recent actual sales (not prices asked) on eBay
with one selling for $3.00 and one for $4.50. Neither was signed by the cachet designer but I would not expect that to add more than a dollar or two at best so your cover would likely sell for something like $5 on an eBay
auction. If you wanted to sell it to a dealer they would not likely pay anything since it would cost them more than that in their overhead costs to put it in their inventory and find a buyer.