The Commodore Plus/4 is a mid-priced 6502-based micro launched in 1984. It is not directly compatible with any prior Commodore machine, but was launched alongside the cut-down-but-compatible C16.
First envisaged by Jack Tramiel as a budget machine to undercut the ZX Spectrum, subsequent management decided to repackage the hardware as a business-lite micro in the C64's price bracket, leading to poor sales. The Plus/4 differs from the pre-existing C64 in its lack of hardware sprites and very simple sound output; however it has a faster processor and a much larger palette of 128 colours. Unlike Commodore's previous budget machine, the Vic-20, it offers a hardware pixel scroll.
Despite never being a huge success, hundreds of titles were available for it contemporaneously and it has enjoyed an extended retro afterlife of fan conversions from other platforms, particularly the C64.