Here's the same item for $12.95.
Amazon - SE Vernier Caliper & Depth Gauge. I bought the same one from Harbour Freight for $10 a couple years ago. It has held up well and remains very accurate. Having 0.1mm precision is good enough for wheel-building (even the $2 plastic ones are fine for that). Once you get in the $15-30 range, you can get much more resolution and accuracy with dial-calipers. But that removes the good lesson on reading vernier calipers.
Here's a
good thread on digital calipers.