Plastic digital caliper

This is cheapest, plastic digital caliper, costing ~$3. LR44 cell probably would be not included, so be prepared. These cells are also dirt cheap (they can be bought in bulk, 10 pieces in a blister for a $1), but these calipers are known to consume them quickly even if not in use (thus cells should probably be removed when not in use).

Why you should reconsider buying these? First, as mentioned: cell may die when you most need it. I've also noticed some kind of failure after time (random LCD segments blinking) requiring to remove cell and insert it again.

Second: accuracy is very poor, maybe not as poor as specified (+/- 0.2 mm would be not funny at all), but jaws are uneven, so results with 0.1 mm differences are frequent.