Uhh I know what a sling looks like, you can RS gold purchase it from cows too. Second cow kill, I received one sling. First kill was an air staff. Also, questing is a challenge for me. I'm terrible at questing. I have no idea which quests to complete or if they're long, I'm bored quite easily. Thus, questing for complete rune armor as well as melee training are the only issues I have.
You can't just turn money into more money. Simply do herby runs practice profitable techniques like hunter longs, fletch yew, anything similar. Someone said 99 fishing that would probably do it but make sure to fish the rocktail angle between 90-99. Yes, you can however it's a very slow and lengthy, depending on the place you begin and how dedicated you are it is possible to turn 1gp into 1B in no time.
The way I'd approach it now that you've got 15M is to purchase something that moves up and down in the price, but it is snared at the bottom by its alch price; at this point you don't want to be taking big risks when you invest your money however, building it slowly. 15 million which is a decent amount will gain you about 400k on each period of the green chaps, for example.
Since they aren't able to drop below 2200 for a long time due to their average alch of 2380,, you are able to purchase them between 2200 and 2500 and sell for 2300-2350. It's not the most efficient method , but it's consistent. if you are a member you are able to purchase more exotic items such as black chaps. They are available for purchase at 5400 and selling at 6000+ but if don't plan it correctly, you can end up holding stocks for a long time.
Avoid red dragonhidesince it's not very popular and avoid seeds as they are the plague, I've lost a fortune in them. The technique is to use the 180 day graph and see what bounces frequently between two points. You can purchase and sell before they arrive at them. It will take some time, but with practice it's possible to earn huge profits of between 1-2 million everyday...do some slayer or woodcutting simultaneously so you are not wasting time.
Herb running (in definition) is the process of running between all of the herb gardens in the most efficient method. It takes a while for people to really perfect an effective route that runs among the ones in the undulating marsh (forget that name) and the one near draynor manor buy Runescape gold as well as the one in the north of Ardy, the one in Catherby and (if the quest is completed) the patch up in Trollheim.