Some computers in the seventies and eighties had the option of output to either a TV or a dedicated monitor. Suppose repurposing an existing TV isn't an option and you are going to be buying a screen either way, which would be cheaper? Are there any figures available for actual prices of monitors and TV sets of similar size in those years?
Based on a quick perusal of the November 1982 edition of Acorn User — a user base reliably rich enough at least to consider a monitor — options then included (size unstated where the advert omits it, but I think that implies 14"):
- colour BMC 1401: £240, £258.75
- colour Microvitec 1431: £269, £270, £284
- colour MC 370M: £289
- unspecified brand colour: £325, £287.50
- green 12" BM[C]12A: £80, £90.85
- green 12" Sanyo: £99
- green 12" Zenith: £95
- green or amber Karga: £113.85
- unspecified and green: £100
- a Sanyo colour television: £235
- TV + monitor (including a PAL decoder, but having raw RGB inputs for a computer that offers an "excellent resolution"): £299
Looking into the autumn/winter 1982 edition of the Argos catalogue — usually a reliable indicator of the low end of high street prices in a given period, I see:
- Network 12" black and white: £49.99
- Philips 14" black and white: £69.99
- Philips 12" black and white with remote control: £69.99
- Pye 12" black and white: £54.99
- Deccavision 14" black and white: £64.99
- Pye 14" colour: £174.95
- Pye 16" colour: £219.95
- Deccacolour 14" colour: £179.95
- Fidelity 14" colour: £189.95
So if that's any guide, it looks to me like the cheapest 12" monochrome TV was almost half the price of the cheapest 12" monochrome monitor. You're getting black on white instead of green but it's far from impossible that the cheapest TV might have omitted filtering of the colour subcarrier; if so then you'd get a pretty decent resolution.
The cheapest 14" colour TV was only about 73% as expensive as the cheapest 14" monitor. Even the cheapest 16" colour TV was slightly cheaper than the cheapest 14" colour monitor.
In both cases the things were quite possibly a world apart in quality — the cheapest TV is a mass-market item in a competitive area whereas the cheapest monitor is already aimed at people with leisure money who are thinking about something they're going to be looking closely at for prolonged periods.