You Compleat Me is a rare Sorcery card from Mystery Booster 2 (MB2), collector number 556. Current market price: $0.16, TCGplayer market prices via Scryfall.
If your life total is greater than 10, it becomes 10. For the rest of the game, your maximum life total is 10. You get an emblem with "Pay 2 life: Add one mana of any color" and "At the beginning of your upkeep, you draw a card and you lose 1 life."