The price of FK bearings is primarily driven by material composition and precision ratings. High-quality bearings typically use GCr15 bearing steel (Chrome Steel) rather than carbon steel. You should verify the ABEC rating (1, 3, 5, or 7); higher ratings indicate tighter tolerances and command a premium price. Additionally, the type of seal (RS, 2RS, ZZ) and the lubricant quality (e.g., Mobil or Kyodo Yushi grease) significantly impact both the cost and the operational lifespan in high-speed or high-load scenarios.