After your character reaches level 55, every time of item becomes available. High level characters get more item types offered to them.Again, except for Rings and Amulets, which are priced 50,000 and 63,000 respectively. The price of items increase alongside the character's level. The items offered are always randomly determined, BUT there is always one Amulet and one Ring.It is common for players to close the screen many times in order to obtain the desired item types. Once the gambling window is closed, the items available on the screen reset.Difficulty, Act or the Npc you choose to gamble with, have no incidence whatsoever in the odds of obtaining a better item through gambling.

Note that the quality of items is determined entirely by the Character Level that is gambling.Gambling can only be influenced by certain items, like for example Gheed's Fortune, that lowers the price demanded by Merchants but does not have a direct impact on the odds of getting a better item. Instead, the odds are affected by your character's level. Difficulty, or whom do you gamble with, does not affect the odds at all.

Item level diablo 2