Whitewater has became a lot more popular in recent times, people often underestimated the game and it was a bit of a sleeper, it is great fun for a beginner and had one of the deepest rulesets to keep even the best pinball players challenged. It also boasts the most ramps of any game ever made.
Nowadays expect to pay 2.5-3k without a topper, I would strongly suggest finding one with a topper as it is without question the best pinball topper ever designed. Very cool effect. You will probally pay an extra $500 for the privilege but it is well worth it (and almost impossible to find later down the track if you change your mind).