I had an epiphany!
Why are hairstyles $20?
It's because you're stuck with it forever unlike other games.
Once you buy that hairstyle....you can still freely switch to any other hairstyles you own.
Normally a reasonable hairstyle price will be $10, but if you got bored of it or saw something better. You'd have to pay another $10 AND lose the older one you previously bought.
You're paying $20 for a hairstyle that will last forever....even if you buy a new one.
You're free to change between them.
$40 bucks for a costume though. I can't justify that.