Granted, the "nickel and diming" of hotline numbers (1900, 0900, etc) was nowhere as bad as today's cash shops, but a lot of us simply forgot they were always hungry for all our money
Here's a bunch other hotline ads for you to peruse - https://www.retromags.com/gallery/category/1729-telephone-hotlines/
PS: I never understood these american numbers that used letters, how were you supposed to know what was the actual number?
and the "DRM" of the day was typing in the third word of the second paragraph on page 6 of the printed booklet that came with the game.
Some games let you keep playing without the correct code... until the difficulty automatically ramped up to impossible levels.