The BBC Model A was created as a lower-cost variant to encourage higher sales outside of the schools sector. It was launched at a price of GBP £235 (compared with GBP £335 for the Model B). This price rose to GBP £299 as Acorn found they couldn't make it at the lower price.
While physically identical, the Model A lacked a number of internal components and interfaces.
16K RAM instead of 32K (although the empty sockets were present on the motherboard). The Model A lacked a 6522 VIA chip (again with an empty socket on the board). None of the expansion ports on the underside of the machine were fitted.