Mini manicures seem to be the most popular thing for the school age girls around me.
They usually book for the start of the week as they will have to take their polish off for going back to school. At least they get the week to wear it then.
I charge £6 for a mini manicure - file, bit of hand cream, paint with Vinylux polish. If they want a bit of glitter I use some Orly FX glitter polish on top.
Most of the girls like a photo taken (no faces or names) and then I put my logo on it and upload to my salon Facebook page. This way the Mum goes onto my page and shares it with all the family (great advertising for me!!)
P.S.
The mum fills in a consent form for each child and must stay with me in the room while I do their nails.