A lot of servers use gp/xp, how is that a scam?
On topic:
It depends on your skills.
If you have 77 rc, blood runes is around 1500 an hour ( sells for 200 each so 300k gp per hour )
Agil pyramid at 75+ is 26 laps ( max efficiency ) an hour ( 260k ) so expect roughly 240k an hour.
There's also thieving, but only becomes good at a high level ( ardy knights can be 300k gold an hour as well )
At 75+ I charge 150k/10k with agil pyramid.