I played this like 15-20 years ago on the PC.

It might have s slightly different name because I basically can't even find one reference to this game anywhere on Google.

It was a sort of RPG. There was a town on the surface where you could click on the icon of a shop and go shopping, or sell slaves, or go into the dungeon/underground.

The dungeon was the real gameplay. It had multiple levels, and the map was a maze of hallways. You would walk the maze and would get ambushed by all sorts of different monsters you would then fight. You could also capture them and have them as slaves.

I remember there being ways of exploiting the game, e.g. you could capture an orc, sell it, and the store would actually pay you when you would buy it back again. This way you could make unlimited amounts of money.

Anyway, I would like to get a hold of this game again for nostalgia reasons. But actually, any info or link or anything would be welcome.

Pretty much yes. If only for a few minutes to pick up daily rewards on MMOs

Strate up MMORPGs:

1. Entropia Universe

2. ESO

Yes, also something from some ancient console you hook up to the TV. Maybe Space invaders or Super Mario or some other obscure ancient game. I remember you would put yellow cassettes in the console, they were hot merchandise back in the day. We would trade them amongst ourselfs... Or maybe even Tetris on some handheld console.

Elder Scroll series starting from number 3.

Baldur's Gate I and II

Elder Scrolls 3: Morrowind