I sold my first program aged 15 back in 1981. It was a version of Space Invaders for the minimum-spec Acorn Atom squeezed into 512 bytes.
That kind of experience doesn't really go away, I still try and first find a clean minimal code before "expanding" the code to make it more easily maintainable.
By selling them to Computer Games companies who would mass produce them for sale via magazines or alongside computers in the early computer stores. In this case I remember the company was called "Bug-Byte".
That kind of experience doesn't really go away, I still try and first find a clean minimal code before "expanding" the code to make it more easily maintainable.