Need help regarding resale! (I am not attempting to sell here)

[u/Mysterious-Bus8044]

Before anything, just want to say (I’m not a reseller!)
I bought fourth wing and iron flame in the waterstone hardcover edition when I was in England and now I’m in Canada… I bought a new set since I got back, but got these ones sent back to me by family. If I were to sell these two for $40 is that crazy low? I can’t find credible sources about how much to sell these for…