Calculators you regret buying?

[Ren]

2 calculators I regret buying,
The first was one of those solar powered 4 banger credit card size calcs that were around in the early 1980s.
As it was credit card sized and thickness, I put it in my billfold. "CRUNCH" when I sat down.

The second (I mentioned a few days ago) was a Casio large screen programmable I bought at a hamfest for $10 over 20 years ago. It came with a thick manual. I did not like it, esp. bin/oct/dec/hex conversions and related calculations did not make any sense to me. Sometime after that I think I donated it.