Many types of runes can be bought from various rune shops for considerably less than their Grand Exchange market value. Many of these shops hold a stock of 1,000 of the basic elemental runes, of which most notably air runes and fire runes yield a notable profit when sold in the Grand Exchange.
As of August 22, 2018, water runes and earth runes have higher shop prices than their Grand Exchange price so those should not be bought unless those prices change in the future.
Teleport to the Al Kharidlodestone, run north to Ali's Discount Wares, and purchase all of the air, water, earth, fire, body, and nature runes. Opening Ali's rune shop requires talking to him and selecting the appropriate dialogue options ("I would like to have a look at your selection of runes." and "Buy elemental runes.")
From Betty's shop, run south to the second-southernmost pier at the Port Sarim docks, and click on the Squire to travel to the Void Knights' Outpost. From your arrival spot in the outpost run south-west to the Void Knight Magic Store and purchase all of the air, water, earth, fire, and body runes.
Return to Edgeville and bank all your items. Make sure you have a knife in your tool belt or are carrying a slashing weapon. Head south to the ruined building in Edgeville and travel to level 51 Wilderness by pulling the Edgeville teleport lever. Exit the Deserted Keep you find yourself in by cutting through the cobweb blocking the way north, and head west to a small ruined building north of the Mage Arena. Cut through the two cobwebs blocking the way and pull the lever to be transported to the small cave where Lundail runs his Arena-side Rune Shop. This is a safe area that is not considered part of the Wilderness and also contains a bank, so you may purchase the runes from the shop in peace. Purchase all the air, water, earth, fire, body, and nature runes.
Some of these rune shops are best accessed via the same lodestone teleports as some stores that sell feathers, so combining the shop run for feathers with this one can save some time.
Players may want to use some of the acquired runes in the Rune Goldberg Machine D&D. In this case, taking the opportunity to purchase some of the less profitable runes to replenish one's supplies may be desirable. For information on profitability of shop-bought runes in comparison the the Grand Exchange prices as well as available runes and which shops sell which, see this calculator.
Changing the buy warning value in shop warning options in the gameplay setting to at least 120,000 will remove any warning when trying to buy 300 nature or law runes at once. This can help quicken the purchasing process.
Due to constantly changing prices on the Grand Exchange, some information in this article may or may not be current. It is strongly recommended to check the live prices on the Grand Exchange before making large investments in any method. All prices on this page are cached, meaning it is possible that they appear out of date. To force a new cache of this page, click this link. If a money making method is out of date, you can edit it or leave a message on the talk page.