1980's computers

TI99/4A wasn't cheaper than the spectrum, it was about £400.
You could buy programs for it (games & accounting software) on plug in ROM catridges. They used to sell them in Argos, I remember looking longingly at the pictures of the TI99/4A in the catalog, before turning to the shower curtains page..

The cartridges were basically a dead end in evolution, unfortunately. They were way too expensive, there were too few of them, they were inflexible, and they often broke (either the cartridges themselves, or the cartridge slot). It was a shame, really. The TI later acquired a disk drive (we never had one and always used cassettes), but by then its time was gone.