How to Make Billions on Runescape

There are many ways to make money in runescape, but I will just go over the best ones. Members have better ways to make money, free-to-play also have ways to earn over 75k an hour.
Free-to-play Methods
1. Mining
Believe it or not, I made over 8m out of mining. To do this, train you’re mining till 15 on copper and tin. If you are poor, you can bank them and sell them at grand exchange, but I do not recommend. Once you get to level 15, you can mine iron which retails for around 50-75 gp on g.e. Train on iron, if there are people already mining iron, hop to another world or go to another mine because chances are that if they have a rune pickaxe or so, they will always get the iron ore. Try to get the best pickaxe available. Train on iron ore from levels 15-45. After you have the ability to use a rune pickaxe, train at dwarven mines, al-kharid mines, lumbridge swamp mines, etc. on coal. Coal retails for over twice the price of iron and you can get around 4-5k an inventory. Continue training at coal or iron till 60. At level 60, this is the big break in making money. At level 60, you can enter the mining guild which has tons of coal rocks and barely any people. I easily get around 400 coals an hour at level 60 mining which is 60-70k. Also there is mithril for people who would want to make mithril bars.
2. Woodcutting
Woodcutting is also a great way to make money, but mostly at higher levels, unlike mining, which only requires around 25 mining to make lots of money. Train on regular trees to 15, then on oak trees. I recommend dropping the logs or lighting them to train firemaking. Train on oaks to level 41 until you can use a rune axe. Try to use the best axe you can so you can work more efficiently. From level 41-70, chop down willows trees. Yews are extremely slow at level 60, so I recommend you to wait until level 70. At 70, they are at a reasonable pace making around 60k an hour. The main disadvantage is that you have to train all the way to 70 in free-to-play to make real cash.
3. Smelting
Smelting the coal and iron ore you mine will also help you make lots of money. If you sell 2 coal and 1 iron ore, you would get around 380 gp, while if you smelt it, you would get around 600 gp. I recommend mining the coal and iron if you are poor because you make more money. Steel bars are extremely easy to sell even at market price because they are efficient on cost-experience.
4. Combat
Bounty Hunter and Clan Wars are perfect for pures, if you aren't a pure, you can still make money by killing hill giants and selling the big bones at 400 each. To make a pure at bounty hunter/clan wars, try to get as low in def and high into 1 stat such as strength, range, or mage. Combining skills is known as a hybrid and is even more efficient. Example of one of my bounty hunter pure has 72 range, 64 str, 52 mage, combat level 51.
Member Methods
*Note, member skills make much more money than free-to-play, (I made around 3m on average a day out of bounty hunter on level 97)
1. Flax/Bowstring
Pick flax at the field underneath the Camelot castle and store them in the bank nearby. Flax retails at 80 gp each and a player could get around 700 each hour, which is 56k an hour which requires no skill at all. You can even make bowstrings in the house which is nearby which raises the value of the bowstring by 50 gp per flax.
2. Bounty Hunter
Whenever at bounty hunter, protect item is a must because if you die with a weapon such as a godsword, you have lost over 40m (depending on the type). Always pack a few prayer potions in middle level crater because people have smite which lowers prayer. Have food which heal at least 16 (i.e. monkfish, shark). Having 52 prayer and ice barrage is extremely useful in making tons of money. Here is a great tip for middle level and high level crater: First, go to the middle of the crater ideally with a clan of more than 2. Whenever a player teleports there, attack him with ice barrage, and put on smite. If you are lucky, 2 people could attack the same person meaning a high chance of death. Once, I had smite and barraged a person with an Amardyl Godsword (114m at that time), I killed him with the help of my friend and he dropped the AGS and picked it up. I didn't get the penalty because I was his target.
3. Killing Bosses
Trying killing high level bosses at like the Kalphite Queen, the level 702 demon (Forgot the name), god wars, barrows, etc. They have good drops which include dragon chain (10m), godsword hilt (20m-80m), Guthan's Warspear (5m). However, these drops are rare and also they are extremely hard and are recommended for higher levels (100+).
4. Skills
Using member skills is also very useful. For example, I fletching yew longs (u) and then using high alchemy on them making 1k plus. Also, slayer is useful at high levels because you can get drops which vary from 1.6m to 3m. However, slayer is extremely hard stat to train. There are also other examples because there are many member skills.
Although there are many ways to make millions in runescape, these are a few which we used.