Party bag for 11 year old?

[TheNameIsDickDarlington]

OK so not a party bag exactly, but dd is celebrating her birthday with 2 friends (she didn't want more, just her two best friends rather than a bigger party)

I wanted to give them something as a "thank you for coming" not really a party bag, although there will be a slice of cake given out, but for the life of me I can't think of what. I've got some cute friendship bracelets for them, but I just wanted a little gift , preferably £5 or under.

Can anyone wiser than me help?

A lip balm and chocolate?
Funky socks?

Yes socks could be a good shout.

My fist thought was a book, but one of them isn't a big reader. Also one of them has quite sensitive skin, so I'm steering away from body wash/bubble bath etc.

Keyring or stationery eg cute highlighters, notebook or pens?