Ok im going to give the one, only, and best way to make money for members. Thats if by the time you read this the prices are not already rock bottom. Last time I checked the prices were ranging from 88 gp- 98 gp.
The way is to buy and sell WATER VIALS!!!!!!!!!!!
Yes water vials, but not the dumb slow way at Arddy but at Rellekka.
Ok here is what you have to do.
Req. Must have finished Fremennik Trials and have completed at least one part of the Fremennik achievement diaries. (Easy, Medium, or Hard)
After you have finished the Req. you go to the place marked in red bringing only your Fremennik sea boots (1,2 or 3 does not make a difference) and money (The more you bring the more you make). I recommend around 50k is enough. (Weight reducing items like the spotted cape are optional) I would also recommend using the lyre to teleport there as this is a fast and time saving way to get their while you can just deposit it after.
When arriving at the Rellekka marketplace you go to the person called Sigmund the Merchant. Buy a full invintory of water vials for 10 gp. After buying the water vials go deposit them at Peer the Seer who should be a bit south from Sigmund.
Here is about how much money you make if you make 100 trips and sold at 88gp per vial.
100×27= 2700 water vials
2700×88(min price on GE)= 237600gp
237600gp-2700(cost to buy vials)=234900gp profit in about 10 minutes
On average if you keep at it you coulds make about a mil an hour selling the water vials at the GE for about 90 gps each. They sell almost in an instant for min price.
Thanks for reading this.