Simply set a price for your collection at a point that you perceive to be slightly above the market value of your cards, and then let Mercari incrementally drop the price until a buyer pulls the trigger
Carrionettes ability is clunky and certainly not mana efficient, but once its in your graveyard you can keep players on their toes, worried about tapping down their mana too far or else Carrionette can carry off their best creature into the most permanent place in the gameexile
At this point, Up the Beanstalk has been clearly cemented as a best-in-class source of card advantage for slower decks
One toughness can be problematic against cards like Orcish Bowmasters, Fire Wrenn and Six, etc., but this is what were working with in Modern
As of 2022, only one copy had ever appeared on the market, selling for a massive $136,000
It's hard to maximize this card, especially with the random aspect, but if you get this to work on three spells it is usually worth it