Woot offers Signature Fitness Olympic 2-Inch Cast Iron Plate Weight Plate for Strength Training and Weightlifting, Style #6 (45 lb - Pair) for $69.99 (reg. $134.99) free shipping with Prime. 

Product Description:
Signature Fitness Olympic 2-Inch Cast Iron Plate Weight Plate for Strength Training and Weightlifting, Style #6, 45LB Pair

• 45-Pound pair
• Made of solid cast iron with a 2-inch center hole fits any Olympic bar with diameter 2” or less; Can be used with 2” dumbbell bars too
• All plates features a durable, black baked enamel finish to prevent the plates from rust and corrosion without any unpleasant odor
• Labeled in both LB and KG for easy recognition
• Weight plates can be used to perform muscle strengthening exercises and endurance training, or to increase flexibility and balance