I think most equipment overall is overpriced.
But if you're gonna splurge spending 300 bucks on a driver that at-best most hit only 12-13 times per round, it would only make sense to be willing to spend an equal amount of money on a club being used twice as often, providing that one is confident with the setup look at address and performance.
I spent $200 on a putter ten years ago, and it was the best investment I ever made in my game.
If you like the look, the setup at address, the feel of the weighting of the club and the confidence it adds to your putting - it's not a bad investment whatsoever, regardless of whatever else anyone else is using and how much they paid for it.
Outside of driver, the putter is the most important club in my bag as it relates to scoring.