My first computer was a Sinclair ZX-81 that had a massive 1K of on board memory, and you could buy a 16K memory expansion cartridge if you had a couple hundred bucks left to spend ...
The 64K memory module was introduced the following year, but it was just Sinclair's way of showing off their new technology - nobody could actually afford the 64K expansion module ...
1982
http://oldcomputers.net/zx81.html
2011
