Does Jewelry itself count if it is played as an Action?
There's no such concept as "playing a card as an Action." It's an Action regardless of when you play it. It always counts itself.
Unlike Horn of Plenty, you could play it with Throne Room or King's Court. Just wondering if you considered that when determining the cost.
She took the pricing advise from me and Something_Smart. I don't know if SS took its Thronability into account, but I didn't think about that.
HoP can be crowned.
HoP only has two Throne Room variants that work on it (Counterfeit and Crown), and even then, one of them trashes the Throned card. Jewelry, on the other hand, has both of those, Disciple, Ghost, KC, Mastermind, Procession, Royal Carriage, Scepter, and Throne Room (10 TR variants). 2 is negligible, 10 not so much. (I'm not counting Citadel because it wouldn't be a useful combo with Jewelry the vast majority of the time.)