I usually give pieniądze.
Can't you think of something better?People who are lazy give money as a gift.
Perfumes-only when you're sure about the scent she'd like.
Cosmetics-not necessarily those for make-up, but maybe a body lotion?
Instead of clothes you can purchase a gift card which is getting more and more popular among Polish people.Just need to know which store she likes best.
Underwear-err... I wouldn't count on guy's taste, unless he's a bit gay lol Otherwise, they usually get something similar to what prostitues wear.Again:you need to know what size she has and what kind of underwear she prefers to wear, i.e.what colour, what fabric, whether she likes frills for a special occasion or maybe just something plain to wear under casual clothes.
Personally, I'd go for the gift card.