The items may sell for more gold than what you offered

Visit the RuneScape Grand Exchange in northwest Varrock to sell your items for gold. You’ll reach a million gold pieces faster if you sell ores unsmithed, gems uncut and herbs uncleaned. To make a faster sale, offer your items for the lowest price. The items may sell for more gold than what you offered if the buyer makes a higher offer. If you sell items such as dragonhide armor, steel bars, ranarr weed and seeds, and rune armor, weapons and shields, you’ll make millions of gold pieces very quickly. However, you can get a quarter to half a million gold by selling lower value items such as arrows, ores, runes and bolts.

Many RuneScape players feel that making gold in the game is a very difficult task. If you know where to look for valuable items and have a way to check item prices, you can easily tell worthless items apart from items that will make you a RuneScape millionaire.
Some ways to make the money.