Maybe Chrono Trigger, it was like $80 when it came out in 1995, and at the time I was earning I think $4.25/hour part time, so that was a lot of money.
...but for real, I Kickstarted Shroud of the Avatar for like $550. "An unofficial sequel to my favorite PC series Ultima helmed by the original inventor of the series and some of his old team? Sign me up!"
Or maybe if that doesn't count, I bought a Turbo-CD for $200 specifically for Ys Books 1 & 2, the game blew my mind with its crazy music and high quality speech, I had to own it.