The merchant

Some rooms hold a merchant. Everything is paid with your account's gold (dungeon loot, quest rewards and run bonuses). Gear you buy goes straight to its slot and replaces what was there, like a reward; runes, gems and charms go to your bag. You can also sell bag and charm items back for a fraction of their value, so selling never beats killing for loot. Prices are D2's, scaled: items and recharges at 100%, gambling at 100%, mercenaries at 20%.

Merchants

Merchant	Services	Stock
Wandering Merchant	Trade, Recharge, Gamble, Hire	3 x weapon (30% magic) 3 x armor (30% magic) 1 x staff (50% magic) 1 x wand (50% magic) 1 x wizard orb (50% magic) 1 x jewelry (100% magic) gamble: weapon gamble: armor gamble: jewelry

The stock is rolled when you enter the room, at item level = the dungeon's monster level + 5, capped at 35 / 65 / 90 in Normal / Nightmare / Hell. Merchants never sell rare items; white items can be Superior or socketed, so look for runeword bases. They also hire out mercenaries from the dungeon's current region (Mercenaries).

Prices

An item's value is (10 + 6 * qlvl + 0.5 * qlvl^2) * rarity multiplier, plus 4 gold per level of each affix and 50 per socket; Superior items are worth 125%, Low Quality 50%. Vendor Prices Reduced discounts buying, recharging and gambling (up to 90%).

Rarity	Price multiplier
Normal	100%
Magic	200%
Rare	300%
Set	400%
Unique	500%
Crafted	300%

Examples (white, no sockets, full price):

Base	qlvl	Value
Short Sword	1	17
Long Sword	9	105
War Sword	31	677
Kingsblade	64	2442
Quilted Armor	1	17
Gothic Plate	60	2170

Item charges ("Level 5 Frost Nova (12/20 Charges)") cast the skill at that level with no skill points needed, only while the item is equipped. Each cast spends a charge. The merchant refills them (Recharge), for 10 gold per spent charge per skill level. Items never wear out: there is no durability.

Selling

Any bag or charm item sells for 25% of its value (quest items and keys are worth 0, so they can't be sold). Equipped gear has to come off first, same as everywhere else: unequip it to the bag, then sell it.

Gambling

The merchant also sells unknown items by base. You pay by your level, not by the item, and get a magic-or-better item at item level = your level -5 to +4:

Unique	Set	Rare	Magic
0.05%	0.1%	10%	89.85%

A unique roll on a base with no unique becomes rare, and a set roll with no set piece becomes magic. From level 25 each gamble has a 10% chance to become the exceptional version of the base, and from level 55 another 10% to go on to elite (if the item level allows it).

Level	Weapon or armor (D2 gold)	Ring or amulet (D2 gold)
5	546	1101
10	1386	3201
20	4506	11001
30	9546	23601
40	16506	41001
50	25386	63201
60	36186	65000
70	48906	65000
80	63546	65000
90	65000	65000