Most Treasured HP Collectible

[Erik-M]

My HP41C , I bought it in 1984 for 791,10 dutch guilders after working on a farm cleaning flower bulbs for a month.
Most students do this kind of work in summer to earn something, spent all on it.
One year later I did the same and bought the cardreader, I still have the handwritten bills.
Two years later I bought the battery pack charger quad memory and x functions.
I do most calculations in Matlab and python nowadays but still use this one to check my code.