What’s a good budget-friendly gift for a sister in her late 30s who already buys herself expensive stuff?

My sister is in her late 30s, has money, and usually just buys herself whatever she wants. She uses good-quality things already, Chanel, Dior, nice skincare, makeup, body products. I'm a uni student so I definitely can't compete with that price-wise. Smth under 20€.

I still want to get her something useful and nice not just random clutter. I was thinking maybe something in the self-care / makeup / skincare / body care category or maybe some kind of practical beauty-related supply.

For women around that age, what's something budget-friendly that you'd still actually appreciate, even if you normally buy higher-end products yourself? Something good quality, useful and not embarrassing to gift when the person already has access to nicer things.