The current market price is 58 gp per arrow.
Mithril Ore is currently 488gp ( Market Price ) in the Grand Exchange.
from grand exchange ~1.6k
In RuneScape, a normal bow and one bronze arrow can be purchased from the ranging store in Varrock for under 100 coins.
I am assuming that you are talking about a bronze arrow (the cheapest and most easily used arrow in runescape). The bronze arrow is usually around 1-5 coins each, and you can obtain 30 for free from the archery shop in Varrock about every 15-30 min. If this question was not intended for runescape, please remove it from this category.
You can buy a Mithril Pickaxe from Nurmof's Pickaxe Shop in the Dwarven Mine, but beware of the much more expensive price offered by the shop. You can also buy it off of the Grand Exchange for the best price in RuneScape shops. It's also possible to obtain a Mithril Pickaxe from monster drops from Living Rock Protectors, Dagannoth Rex, and Living Rock Strikers.
99k
725m 725m
$15.00
Around 2k
around 100 gp
2Mill
I believe there is around about 4 rocks I haven't been there for a while.