Air runes are the most basic runes to run. You only need to buy regular rune essence to have them created, but you should only use this method to gain initial wealth to move onto running Law runes or Nature runes to gain more money per trip.
The Air rune altar is located south west of the southern Falador city exit, which, if you are leaving out of the southern exit of the city, you should just head on an angle to the right through the grass next to the path. The altar should be located a couple paces into the grass. I would not suggest using teleport runes at all with this altar because of how close it is to Falador's bank.
Running Air runes is designated, by Runescape's creators, as being located in world 16, which is a free to play world. You could also go to Runescape's forums to find a private player or clan to run for.
Air runes are not the runes to run to strike riches fast; rather, it is a strategy to help you get started in the game. Many times, people run air runes to get initial wealth or just to get runes for their Magic skill training. The only way you can really make money off of this technique is to mine the pure essence yourself, and/or run Air runes for higher Runecrafting leveled players which can make multiple amounts of Air runes per rune essence. This can be done by running runes for a person with a high Runecrafting level.
Here are the levels with the amounts of Air runes made per rune essence:
Level 11 = 2x the amount of Air runes per rune essence
Level 22 = 3x
Level 33 = 4x
Level 44 = 5x - (Runecrafters usually move to making Nature runes so this may be the highest level you will see Runecrafting Air runes for rune runners.)
Level 55 = 6x
Level 66 = 7x
Level 77 = 8x
Level 88 = 9x
Level 99 = 10x
So, this means that a level 11 can make double the amount of air runes per rune essence, a level 22 can make triple the amount of Air runes, and so on. Usually by level 44, the Runecrafters move to making Nature runes for rune runners, because they will receive more experience. We'll talk more about that on the next page.