Old/decommissioned freeway or highway signs for sale?

My dad’s birthday is next month. He’s been collecting metal signs for his garage (mostly free ones he’s gotten from his job). I thought it would be cool to get him a freeway or highway sign. Nothing like the big exit signs, but like an I-10 shield sign or something similar to that. Does anyone know if TXDOT sells anything like that to the public? Or potentially where I can procure something like that?

Thanks guys and have a good one!