I loved them all, but if I had to choose
Descent 2 > Descent 1 > Descent 3
3 was a well done transition into a new type of game engine. Good advancement of the story. Worth playing if you are a fan of the first 2. Felt like the developers cared for and stuck to the vision.
Usually, but not always. Some 5-10 year old games are still north of $50. The price for some movies and TV series has gone up rather than down over the years.
Luckily, as you said there’s so much out there that as long as I don’t get too picky there’s more than enough available without paying gouged prices.