|My first programmable device purchase: Texas
Instruments SR-52 Programmable Calculator. (Summer of '75, $395)|
It had 224 steps of program memory with 20 memory registers.
Also had a motor-driven card reader for non-volatile storage.
With work, and a lot of squeezing, a two-card program (448 steps) could solve a 4x4 determinant in about 3 minutes.
It had a game "Lunar Lander" that provided hours of distraction.