These are neat. Not but I'll try. I'm looking at B/X and I'm just going to wing it based on costs of making magic items, treasure tables and being inexperienced. Everyone feel free to tell me I'm fucking it up and why.
Soul of the Crystal King, depending on how long they've been dead for, what they have title to, who's looking, their family, their rivals, a necromancer trying to stage a coup, a psychopomp trying to send the soul to hades, etc. 5000gp and up, make an offer. I'd try and trade it for political position personally.
Mida's Calligraphy Set. 500gp. Its a well made cool thing. But its not magic.
Key of the Fallen Moon. I'm assuming its hard to get to the moon, and the key does something there. So its not really that valuable except to specific moon oriented people, otherwise its some nicely worked jewellery. 600gp unless a special buyer in which case much more. Seems like a better quest hook.
Lycanthropy Heart Transplant Cure. 1000gp, its magical and fascinating, but not super useful. Its cool though, and I'd try to have a rumour table about who's heart it is, maybe them wanting it back. 10000 to the Death Knight who lost it?
Horse Whisperer Statue. Do they know its a queen or do they think its a life like statue? Are there still horse people who want their queen back? 500gp for a statue or everything the horse people have for their queen. Lets say 10000, horse barbarians on call, etc.
Theoretical String. 100gp per inch. Not sure why, just seems about right.
Doll Eyes. 2500gp. Kind of like cure serious wounds, kind of like remove curse. Added an extra 500gp because they seem better than a scroll of 'regenerate eyes' in ways. Put them in backwards and see into your soul!
Instr-Dragon (already a cool name and I'm running out of ideas), depends on how we determine dragon type. They're treasure type H, which is suppose to average at 50000 so 20000 feels right. Its worth a lot. You can basically ruin anything's day with this.