Sinclair certainly competed vigorously on price, and designed their machines to achieve as low a price as possible. The ability to sell a computer for less than £100 was one of Clive Sinclair's goals with his earlier ZX machines, for example. One example of this influence on the Spectrum line was their membrane keyboard, another was the fact that they were sold in variants with less RAM (which was one of the more expensive parts of a microcomputer.) Price was a key area of competition between manufacturers throughout the 1980s, with manufacturers trying to meet and beat each others' prices and specifications.
A dig through the August 1983 issue of the UK's Your Computer Magazine (found on archive.org) includes advertisements from several retailers of microcomputers, and a full-page spread advertising a price drop for the Spectrum.
The 16K Spectrum was newly reduced from £125 to £99.95, and the 48K Spectrum was reduced from £175 to £129.95.
A nationwide dealership (confusingly named Spectrum) advertises the Commodore 64 at the much higher price of £345, as well as a clearance deal on Commodore's VIC-20 at £139.99. They offer the ZX Spectrum at the reduced prices mentioned above.
Other manufacturers' machines (with RAM sizes) offered by this retailer are priced as follows:
- TI-99/4A: £149.95
- Atari 400 (16K): £149.95, 800 (48K) £299.95
- Oric 1 (48K): £169.95
- Dragon (32K): £175
- Colour Genie (16K): £194
- Lynx: 48K £225, 96K £299
- BBC Micro Model B (32K): £399
- Sharp MZ-80A (48K): £546.25
As you can see, the price drops on the ZX Spectrum placed the machine cheaper than any of these competitors.
The BBC Micro was expensive compared to the competition, but it was very highly specified, with all sorts of expansion interfaces. It was more popular in the education and technical markets. Acorn introduced the Electron to try to compete at a lower price point, but it was late to market and had limited success.
One year later...
By November 1984, the same retailer is advertising the Commodore 64 with joystick, cassette recorder, and 4 games at £249. The new Commodore 16 (with only 16K RAM) is sold with a cassette recorder for £139.99.
Other machines haven't dropped much in price, but have bundled extras. The 48K Spectrum is still £129.95, but has 6 pieces of software thrown in for free. The BBC Model B is still £399, but now includes a cassette recorder and 5 pieces of software. Acorn's Electron is priced at £199.95 for the machine only.