Now that free trade has become available I started playing a little Runescape again. I was looking for an easy way to some money so I started doing a little merchanting. I was looking for quick cash as I needed to buy some bones for my pker. for this strategy I suggest having at least 2m+ to invest as you will be making around 24k a flip with it just that. I choose the rune scimitar to flip as I was online during peak pking hours and its obvious that players are wanting to sell the ones they get from kills and buy more when they die.
At the time of me writing this tutorial the suggested purchase price is 21639 gp per rune scim. I went ahead and clicked the lower 5% and then lowered it again by 5% so I would be purchasing them at 19529 gp each. (Yes you can go lower but it does take longer to purchase them) it took me about 3 minutes to purchase all 100 the first go. I then quickly turned around and set them to be for sale at 20,000gp each. The reason I choose 20,000 is that its an easy to input when a purchaser is trying to get a lower price for an item. You can try just lowering the suggested price by 5% but I find that they do not sell fast enough.
Now here I am a few minute into using this method I start setting the sell price for slightly different values to see if the market is shifting. If I sell the rune scims for a higher price I know I need to always sell at the price until the wave and I need to lower again.

Here is a picture 10 minutes into using this method as you can see its 75k profit in just a short period of time. Yes this may not get you rich in just 1 hour but with about 5m you can earn close to 1m in 4 flips alone.

This method seems to be working well for pretty much all pking equipment with the exception of amulets.
