I just bought mine, but they are handmade so obviously made with love . try a local craft shop or cwa store or opshop. Mine are new ones that they sell in the second hand store. They have lots of other gorgeous knitted things too. They had the most beautiful baby shawl, all hand knitted.
I put both booties in my pillow case, I might put one in my OH, if I can sneak it in. He laughed when I told him , but he didn't stop me. I wasn't at all surprised by his reaction, it is pretty much what I expected.

Good luck, I think there will be a shortage of yellow booties now . fingers crossed it works for us all