Are expensive cosmetics worth it?

For some reason, maybe because I’ve been researching this article for a while, google thinks that I want to buy anti-ageing creams. Wherever I surf, I see ads trying to sell me all sorts of wonder cosmetics designed to reduce my wrinkles. Retinol this, vitamin C that. I even found a cream that costs 700 dollars for 50 ml (or $14000 a litre!). But do these creams even work? Are they really worth the money? Are there any valid scientific studies on their effectiveness? (Spoiler: nope).