Gheed is abusing my addiction. What are my odds when gambling in Diablo 2?

So, I've just picked up D2 again to play with a friend, and we both have been giving that jovial fellow Gheed the majority (read: all) of our money for the chance of decent items.

What is the chance of getting rare/set/unique items from the various gambling merchants throughout the acts?

Solution 1:

From the all-knowing Arreat Summit

The items you receive will be from most common, to most rare: Magic Items, Rare, Sets, Uniques. Set and Unique Items are extremely rare. The chance for Uniques is 1 in 2,000 (0.05%) and 1 in 1,000 (0.10%) for Sets. The chance for Rares is 1 in 10 (10%). Magic Items are 1/~1.1 (89.85%).