Waterdeep Goods and Services

Coinage

Waterdeep honors all coinage, trade bars and electrum in 10-, 25- and 50-gold piece weights from throughout the Realms, as well as gems (which are traded as currency, rather than simple art objects, due to generations of dwarven influence).
Toal (2gp): A square, flat brass coin issued and honored by the Lords' treasury. Very little value elsewhere.
Harbor Moon (50 gp): Technically worth 25 taols, harbor moons are crafted of platinum inset with electrum, in the shape of a crescent with a hole cut into the center of its curve. Traditionally used for buying large amounts of cargo. Worth about 2 platinum outside Waterdeep.

Changing one form of currency into another is a thriving business.
For small amounts of coin, the moneychanger generally charges a simple 10% fee, keeping "one coin in ten" of the transaction.
The rate for larger amounts of coin can often be negotiated down.
Moneychanging explicitly includes not just minted currency, but gems, trade bars, furs and the like.

Moneylenders are respected citizens in this trading city; everyone needs extra coin from time to time.
Loans involve the written promise of collateral in the form of property (which becomes the lender's if the loan is not repaid), and written terms of interest with a time-limit.
Most loans are for one or two months.
Most loans have rates of interest from 15% for small loans (anything less than 100gp), to up to 30% for very large loans.
Usury (charging outrageous amounts of interest) is illegal in the city, though there is a thriving shadow-business of usurers who make loans to those no one else will lend to or to those who need large amounts of coin outside the public eye. Such loans are established with a handshake, and enforced through thugs and cutthroats.

Waterdeep collects no annual taxes, but raises its revenues by the charging of fees, as follows:

1 copper piece per market stall per day, collected between sunrise and sunset by any city watch patrol, who issue receipts for fees (to show later patrols the fee has been paid). This buys the exclusive use of that location from sunrise to sunset, security patrols by the watch, and freedom to sell goods at whatever the market will bear, rather than at prices set by guilds. Guilds pay these fees for members, out of guild dues.
1 silver piece (above any fines) from any person convicted in a Magisterial or Lords Court, per conviction.
1 gold piece per caravan wagon leaving the city, empty or full.
1 gold piece per sword sold (fee included in the price, and submitted by the vendor to a Magister or the watch within ten days); all blades sold in Waterdeep are thus taxed and registered, and Magisters deem anything with a blade over one foot long to be a sword. Other weapons are not so taxed; hence, many citizens of Waterdeep use clubs and daggers (shady characters use garrotes, hidden daggers, and lassos).
5 gold pieces per ship that docks in Waterdeep, collected from the captain. It covers a stay of up to fourteen days, provided the ship does not leave the harbor and return during that time, which ends the stay and begins a new one. This fee covers watch patrols, the dock space, fresh water, ballast supplied if desired, and the right to dump ballast or spoiled cargoes in an agreed-upon area under the direction of the watch (and a complement of mermen guards).

In times of trouble, direct taxes may be imposed:

a fire tax (1 gp per household), levied whenever fire destroys a large portion of Waterdeep
a wall tax or harbor tax (1 gp per household), raised to pay for needed repairs or expansions
a lance tax, raised for a payroll for mercenaries hired by the City when required (usually 1 silver piece per household each week until the Lords repeal the tax).