Calculators you regret buying?

[ijabbott]

This is a counterpoint to the Calculators you regret not buying? thread.

This thread is for calculators that you regretted buying for some reason, probably because it did not live up to expectations. Preferably, it is for calculators that were available new and bought for actual work or study purposes rather than for collection or playing around.

I regretted buying a Casio fx-3800p. At the time, I was already using a fx-450 quite heavily for its "computer programmer" features, so the vinyl covering of the spine connecting the two halves of the keyboard (proper keys on the left side, membrane keyboard on the right side) was getting the worse for wear. I went to the big chain newsagents (WH Smith) in town to pick out a new calculator and picked out the fx-3800p for about 30 UKP. It seemed to check all the boxes: hexadecimal, octal, and binary calculations, and as a bonus it was programmable too. The regret part came when I discovered that despite supporting common number bases for computer programming, it did not support any bitwise logic operations. Also, the programming capabilities were much more limited than the Casio FX-502P that I had bought from new several years earlier, and I regretted the fact that this feature had regressed rather than advanced in the newer model.