Cheapest Scientific Calculator?

[damaltor]

I have a clone of a casio casio fx-991ms labeled Olympia when i remember right. It was a business gift, so i do not know the original price, but as a business gift it probably was far below $5. It looks like the casio fx-991ms and even has the same easter egg / test mode like the original, but has extreme low quality with badly working keys. I guess it has the same software but far inferior hardware, though it looks almost identical.