It was generally around 10-12, I think it peaked at 15 when they were in very high demand. It was the frustrating to many new players (myself included) since it was sort of the one semi-big expense you used to have to shell out to start playing competitively.
Tropical Beach has been absolutely terrible for the format--because it limited a lot of decks most players could use. A lot of people say "oh, well there are plenty of good decks that don't use beach!" but that's an unfair assessment. There are tournaments where Blastoise or Rayboar are the best plays, and anyone without beach was simply unable to play those decks at a competitive level.
For now though, I'm content to just let it rotate (which it will, assuming they have a standard rotation). It's the only way to "ban" the card in a predictable manner so that the players who own beach don't lose hundreds of dollars on no notice. I wouldn't mind seeing it reprinted after that--the effect of the card is actually very good for the game--but the price tag right now is just awful.