You can gamble as much as you want, for a while, the gambler could also drop money, but that was too exploitable. At least now, you need to give up buying regular upgrades and hope to get %-increases of the ones you already have. Or, do what I do, do it in the end of the game, with all money you have left.
There are not ore enough for all vendors, I suggest, for better players, to go offense and vitality shops, you need the damage to kill faster and health for one the hits you take. Armor is only good if you get hit often, which you want to avoid, that's why you level move speed.