The two things that come to my mind aren't that close to "golddigger" really.
Naciągaczka (Instrumental: naciągaczką) - someone who plots to cheat you out of your money and stuff, but that could be as well used to denote a vendor who wants too much money for the stuff she's selling
Blachara (from 'blacha' = 'sheet metal', the thing in which cars are covered; Instrumental: blacharą) - a woman who gets interested in the man mostly because of the car he owns.
"możny" nowadays means rather someone with huge power and influence. It's not a common word. It used to mean someone very rich, though.
Nowadays you can say "zamożny", it's more or less like "wealthy" - a less common, but used word for "rich".
I was going to use wealthy but upon checking, found It wasn't an posted option