A late 80s / early 90s BBS is no comparison. Cost-per-everything in computers had plummeted by then--even kids could host a BBS with the family computer.
Per wiki on Prestel (i know it's videotex, but the article covered both):
Hosting Costs:
> In 1985, British Telecom estimated that for an IP using a typical minicomputer (such as the PDP-11) located 100 km from London and handling up to 10 users simultaneously at peak times, the one-off software set-up cost would be at least £16,000, communication costs would range from £4,280 to £5,550 a year (depending on the type of connection), and Prestel usage would cost £8,600 a year.[82]: 4
Usage Costs:
> At the launch of the commercial service in September 1979, and in addition to phone charges, users were charged 3p per minute online to Prestel from 8 am to 6 pm Monday to Friday, and 3p for three minutes at other times. Installing a phone jack-socket cost £13, with a quarterly rental of 50p. Business users paid an additional standing charge (i.e., a flat charge regardless of usage) of £12 per quarter.[23]
> By October 1982, the online usage charge had risen to 5p per minute (8 am to 6 pm Monday to Friday and also 8 am to 1 pm on Saturdays, free at other times), the business standing charge to £15 per quarter, residential users now paid £5 per quarter, and jack installation cost "from £15", with a 15p quarterly rental fee.[24]: 2
Content Distribution Costs:
> A main IP rented pages from the Post Office (initially) or British Telecom (later), and controlled a three-digit master-page in the database. In 1982, this cost an annual £5,500 for a basic package,[24]: 1 equivalent to around £29,000 in 2021.[80]
Prestel was something else. It was a teletext style system, but teletext was on every TV in the UK after the BBC started broadcasting CEEFAX (their service) and ITV started providing TELETEXT (their service). Channel 4 also had a service, but I don't remember what it was called.
Teletext was using the same style of presentation (BBC Micro had mode 7, and this was Prestel/Teletext compatible.) But Teletext was one way - it was broadcasted as part of the TV signal and your TV would decode the data and display it. If you wanted a specific page, you entered the number and then the receiver waited for the broadcast to get to that page and it decoded it and displayed it. There was no uplink. It all happened as part of the transmission and all of the pages were transmitted serialy in order so you would feel like entering in 123 would load page 123 directly, but actually it was displayed the next time 123 was transmitted.
Prestel was something else. It was a teletext style system, but teletext was on every TV in the UK after the BBC started broadcasting CEEFAX (their service) and ITV started providing TELETEXT (their service). Channel 4 also had a service, but I don't remember what it was called.
Teletext was using the same style of presentation (BBC Micro had mode 7, and this was Prestel/Teletext compatible.) But Teletext was one way - it was broadcasted as part of the TV signal and your TV would decode the data and display it. If you wanted a specific page, you entered the number and then the receiver waited for the broadcast to get to that page and it decoded it and displayed it. There was no uplink. It all happened as part of the transmission and all of the pages were transmitted serialy in order so you would feel like entering in 123 would load page 123 directly, but actually it was displayed the next time 123 was transmitted.