At time of writing, there are only two listings for the non-foil version on the Marketplace, the lowest of which is just over $1,200
Earn 41 free BoM points
While she's not the most expensive card in Ultra Prism, Cynthia maintains an incredibly high value that would usually be more than enough for the top spot
As for Twin, your best bet with Tas is either to switch to Grixis Twin, or to use one of the other substitutes I'm about to cover
And then you'll have fuel with Food which counts as both artifacts and tokens, Treasure decks, Clues, Orzhov Tokens, and more
If you want to get really crazy, you could run Festering Newt, Bubbling Cauldron, and Bogbrew Witch