Texas Instruments TI-30. The calculator that broke the price barrier.

The first hand held scientific calculator was the HP-35 that came to market in 1972 at a price of $385 USD. That would be equivalent to $2400 USD in 2019. This was too expensive for anybody except the best funded professionals. Prices declined over the years, but the biggest price break came when Texas Instruments introduced the TI-30 in 1976 at a price of $25 USD. That is equivalent to $113 USD in 2019. At that price point, scientific calculations were within the reach of nearly everyone. Inflation Calculator: https://www.usinflationcalculator.com/ The HP-9100 image is from The Museum of HP Calculators. This is an excellent source of information on the history of HP calculators. The HP-35 and SR-50 images came from Wikipedia.