PicoCalc is a $75 portable handheld computer

Clockwork's PicoCalc is a handheld portable computer powered by a Raspberry Pi Pico H (you might well want to upgrade to wireless). It has a qwerty keyboard, 320×320 display, SD card slot, integrated speakers, a 3.5mm phone jack and an 18650 battery compartment. At $75, it's the company's cheapest model yet.

ClockworkPi v2.0 mainboard
Raspberry Pi Pico 1 H Core module (ARM32-bit Dual-core Cortex M0+, 264KB RAM, 2MB flash)
320×320 4-inch IPS screen (SPI interface)
Ultra-portable QWERTY Backlit keyboard on board (I2C interface)
Dual speaker
ABS plastic shell & 2.5mm Hex key
Tempered glass cover
32GB high-speed SD-card with optimized BASIC firmware

Every day is another struggle to not pull the trigger on a DevTerm; now I have two problems. Batteries are not included, but the source code certainly is.

Previously:
Mecha Comet is a handheld everything machine
Hackable Raspberry Pi handheld computer
Cool linux handheld computers coming in 2018