On my honeymoon in Hawaii (humble brag) I bought a wood post card and didn’t believe that it could be mailed with regular postage. I was wrong. I knew I had to make my own some day. I mean, who doesn’t want to receive a wooden postcard in the mail?
Be warned, there are restrictions on what the post office will allow you to send. I have done the troubleshooting for you, so all you have to do is follow the rules. As long as you follow these rules, you can mail a piece of wood at regular postage rate plus a “non-machinable surcharge.” It’s all less than a dollar!