@Canageek How about using a luck point to re-roll an arcana check in a seedy shop. On the re-roll you get a 20. The DM hands you the item card. It's a legendary artifact and perfect for your character. "I calmly ask the shop keep how much she wants for this?" The DM smiles wider and points to the last line on the card.
"Cost = 3 luck points at time of purchase"