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 ojnkijninb8uyb90-hunohj9-8unj 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 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 coins per cast on average.