One good source of runescape gold sell and useful weapon are Diamond bolt (e)
Making runescape gold from diamond tips
Diamond bolt (e) is one of the powerful weapons that you may have to defeat boss monsters so it may give you more runescape gold sell. This powerful weapon is a result of enchanting a rs items Diamond bolts a combination of adamant bolt and diamond bolt tips. Checking of rs gold price of this on the player auctions grand exchange is recommended to avoid spending more.
How to make diamond bolt for your way to runescape gold success
Buy tons of diamonds in Grand Exchange; put some of the diamonds in the bank. With a chisel in your tool belt, withdraw some diamonds. When you chiseled the diamond, you will gain 12 tips. Chiseled the entire diamond you have. Once you chiseled the entire diamond especially in your storage, start selling them in Grand Exchange to make more Rs gold.