School uniforms were the first thing that came into my mind.
They are incredibly expensive, I think my kid's uniforms were worth more than my entire wardrobe.
But when you think that they will be worn every day of the school week it's a lot easier to see the value in them. And of course they are passed down to the next child, increasing the value for money.
So while they cost a small fortune, they are well worth it in the long run.