Cheaper single 1/5 inch piezo pickup to use with K&K system vibraphone?

Hi!
My funds are limited. I have the K&K pickups. It is an older set so some pickups are failing and need replacement. Official K&K pickups are about $22 each plus shipping. Does anyone know of a source where I can purchase complete, ready made but less expensive, single piezo pickups to use with K&K system for vibraphone? THANKS!