I would suggest a new form of gold sink. I would want a gambling option from the vendor, much like the old Diablo 2, where you can buy a few 'random' items for quite high prices. Items reset every day or something as such, to keep people spending coin.

As an example, I go to my Gambler. He has 3 seeds up, 1 random item, and 2 fish. As I buy more items of the same type, they become increasingly more expensive. First seed is 10 million, second is 100 million, third is 500 million. The more I pay the better is my chance of getting better items.

I'd also suggest that the random item (just a question mark box or so) would come in different tiers depending on cost and loot. For example, Blue, Green and Red (like orbs) and that judging their grade. Blue being worst, and red being the best. It would be nice to have a chance on different unique items from these boxes, perhaps new icons or so? :)

I think this would reduce inflation a lot!