Idk what to give my dad for his birthday!!!

Hey all, my dad’s birthday is on June 21 and I have no idea what to get him. He really likes books about military history (he was a marine) but all the ones that I find with the best reviews he already has (With the Old Breed, Helmet for My Pillow, Gates of Fire, etc.). He also likes working outside but everything I’m finding for outdoor work is super expensive. Please help!