A CNC probe is pretty darn expensive, a
few hundred of USD, and for a reason, they do a great job, they are
pretty finicky things to make, they last for ever (or until you crush
them by mistake because you forgot to plug their cable in before
launching the cycle) Now you can 3D print your own
C..
Normally a calibration probe for Z axis
is enough for 3D printer, be it a magnetic sensor, a hall probe like
BL touch or a simple switch that clicks at touch.
Not true when you work in 5 axis, your
bed tilts, and needs calibration mapping before every print
individually. That is another beast ..