The law staff is a magic weapon that costs 10,000 Dungeoneering tokens and requires level 45 Dungeoneering and 45 Magic to acquire and wield. Players can store up to 1000 law runes within it, and when used it has a 1/10 (10%) chance of not using a law rune. This effect also works with spell tablet creation. Law staves do not stack in the bank.
Although it may seem as though the law staff's ability would save the player more money due to law runes being more expensive, the fact that there is only a 10% chance of saving a rune means that the monetary savings after 10 teleports only amount to 570 coins (the price of one law rune). With a staff of air or similar staff which provides unlimited air runes, the savings for the same 10 teleports amount to 2700 after preserving 30 air runes, proving much less costly in the long run. The law staff does save more money when casting Telekinetic grab compared to using a staff of air, although the margin is a tiny -33 coins per cast on average.
Most free players prefer using the nature staff to law staff in combat due to the higher attack bonus of the nature staff which is 931 while that of law staff is only 732.
The following is a comparison of the cost per cast of spells using law runes while using an elemental staff as opposed to using a law staff. The cost per cast when using the Law staff is approximate and assumes that exactly 1 out of 10 Law runes are saved.
Standard spells
Example on reading the table:
The cost of Varrock teleport using a fire staff is 840 gold.
The cost of Varrock teleport using a law staff is 942 gold.