If I were to buy an LED model...

[Maximilian Hohmann]

Hello!

The cheapest LED model is probably the HP-45. They are in plentiful supply and it is still possible to find them here (in Europe) for 30 Euros or less. Maybe not in perfect cosmetic condition, but they all work. I have yet to see a non-working HP-45. Mark Hoskins will sell you a battery pack with more modern batteries than the original ones which can still be charged with the original charger but will last for many hours. Unfortunately the HP-45 is a little boring and not able to do much.

My personal candidate for an LED model - if I could have only one - would be an HP-25. That one is _the_ Woodstock calculator. It came out early, yet is programmable. The "smarter" successors (25C, 27, 29) came later, or rather too late to be produced in large numbers, and fetch crazy prices on the market which they are not worth. For a collector maybe, but not for someone who just wants an HP calculator with LEDs. A working 25 can, with patience and luck, be found for less than 100 Euros here. Or you buy a non-working one cheap and put one of PANAMATIK's low-power boards inside. But this is no low-cost solution...

And if you want the ultimate LED calculator from HP you need to look for an HP-67. That one is the latest (and best - or at least equal to the Ti59) LED calculator ever designed. But they have become rare and rather expensive and usually require some maintenance (card reader) before they can be used.

Regards
Max