Many Commander staples (cards good in lots of decks) like Sol Ring or Arcane Signet are pretty cheap as singles (Sol Ring around $1.40, Arcane Signet $0.49)
One of the first things that I thought of after realizing that Final Fortune wasnt in the mix was to think of the other cards that might make sense to exploit
Then, anytime you attack with either an Insect, Leech, Slug, or Worm creature, the defending player loses one life, and you gain one life
A very easy price for removing an opponents greatest creature
Creature - Human Noble Kayla's Command Choose two Create a 2/2 colorless Construct artifact creature token
When you cant find a local buyer for your single card, you want the most value possible for it, you dont want to bother setting up a TCGPlayer sellers account, and youre willing to tolerate some of the worst people outside of Reddit, eBay is where you turn