9

While interacting with NPC's, I discovered the "gambling option. I decided to try it out.

Players can interact with an NPC and select the "Gamble" menu. There is a window with Unidentified Items. After spending some money on a specific item (by right-clicking on it) the item gets identified and the stats become known. After the rift, I gained a lot of gold and thought it might be a good idea to put some in the system.

The game showed these chances for every item quality:

Unique: 1/2000 (.05%)

Set: 2/2000 (.1%)

Rare: 200/2000 (10%)

Magical: 1797/2000 (89.85%)

Opening the gambling screen generates all the items shown in the window, even if they are never bought. This means that if it spawns a unique item, it won't spawn again in the same game. I left and re-entered the game after the prolonged gambling session. 

I also found Kanai's Cube. Prices in her store depend on item type, most of the armor costing 25 shards, jewelry 50-100, and weapons 75. There is a 10% chance to roll a Legendary or Set item in her store, regardless of difficulty or magic find. She does not sell items that are only found in Horadric Caches, but will sell Torment-exclusive items.

Upon every poor purchase, Kanai will laugh, saying that 'maybe you can find a use for the item they just bought one day... as a paperweight'. She will, however, congratulate you on a good roll.

Using Kanai's Cube to upgrade Rare items is a way of Gambling, for players only choose the type of item they want to receive, but the resulting gear is subject to random factor. 

I didn't win anything but it was probably for the best, especially after the abundance of items and gold won during the rift.

NPC's throughout the game that are able to start the gambling screen:

Gheed - Rogue Encampment 

Elzix - Lut Gholein 

Alkor - Kurast Docks 

Jamella - Pandemonium Fortress 

Nihlathak / Anya - Harrogath