TI graphing calculators boot to BASIC. I don't know about the newer ones but the old ones are extremely simple computers with Z80 or 68k processors and hardly any operating system, fun to program in BASIC or assembly language or C.
Modern kids might find them boring but they are great places to learn how a computer really works without piles of modern software cruft between you and the hardware. That's where I learned.
For those interested in hearing more about TI calculators and hacking on them, this episode of the Embedded.fm podcast was really fun, and there are a couple interesting links in the show notes: https://www.embedded.fm/episodes/259.
Modern kids might find them boring but they are great places to learn how a computer really works without piles of modern software cruft between you and the hardware. That's where I learned.