Keldon Halberdier is a common Creature — Human Warrior card from Time Spiral (TSP), collector number 167. Current market price: $0.25 (foil $0.54), TCGplayer market prices via Scryfall.
First strike Suspend 4—{R} (Rather than cast this card from your hand, you may pay {R} and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)