The gem stall
The coin faucet: one stall by the bank, no requirements, and a guard who turns up eventually.
One gem stall stands beside the Edgeville bank. It is open at level 1, has no gates of any kind, and is where the game's coins come from.
What it pays
Coins and Thieving experience, scaled by your Thieving level and by nothing else. At level 1 that is around 496,000 coins an hour; at 99 it is around 1.48 million. There is no gear bonus, no outfit and no trick - the level is the whole rate.
::market walks you to it and says what it is currently paying you.
The guard
A Market guard turns up every 140 to 220 steals. He is the only interruption, he is beatable, and he is why the stall is not a completely idle activity.
Why one stall and not a row of them
Thieving used to pay items - a cake, a jug of wine, a chisel - and every one of those can be conjured out of the item spawner for nothing, so the whole skill paid zero. Coins fixed that, and one stall by the bank keeps the faucet somewhere it can be measured rather than spread over six stalls nobody watches.
What coins are for
The Armoury sells gear, Supplies sells everything a trip burns, and the General Store buys your junk back. Alchemy is switched off, so the stall and the store are the two ends of the coin economy and there is no third.