You can go to Taobao to find it. If you give it away, you can buy an album "War of Love" released by him more than ten years ago, but the album is generally unsigned.
Generally, one of his books, The Play from Heaven, is signed. Don't buy signature photos on Taobao. It's fake and meaningless.
You can also buy a diamond sutra. Anyone who likes Lao Wu knows the meaning of Diamond Sutra.