What to buy girls age 8, 9, 10 and 11

[OhCobblers]

I don't know them well and would like to give them a small surprise up to £15 max. Presumably 8-9 year olds would be a bit different in their taste to the 10-11 year olds?
Any ideas gratefully received!

Nail varnish
Anything from claires accessories

My DDs are 8 and 9. Some things of around that value that they have liked recently are the Tom Gates book collection, The Encyclopedia of Immaturity, sylvanian ice cream van and ice cream vendors (separately possibly just about balance out around £15), scarves from River Island and Fat Face, disposable cameras, Moshi figures, fancy felt tips.
Slightly older nieces in the past have had fancy art materials, lush toiletries and bath stuff, teen perfume sort of stuff.
All of the girls in my family have been more on the girly side though, the ones you are buying for might not be!

VIP pet or Zelfs for the younger one, maybe even the 9 year old with a fancy notebook and fluffy pen? TBH, all the girls I know/buy for like little notebooks/notelets/card making sets actually.
The older two I agree you could do teenager perfume or bath bomb/face mask labs. Anything like that would go down well for girls of those ages.