They learnt how to make their crafts from another stallholder at the market, Jan of Jansfelts NZ, says their mum Ruth.
"They were invited over on the holidays and she taught them how to make these things," says Ruth.
The girls will also be selling vinyl mugs which are being made by a friend's mum. They are also hoping to sell some gingerbread biscuits and to have a lucky dip.
The market runs from 9am to 2pm and their store will be inside the community hall.
Isla is just 4 years old and was diagnosed with leukaemia about nine months ago.
She has been in and out of Starship to get her treatments since the end of the Covid-19 lockdown in March last year.
"She is suffering and going through a lot of pain and she's only 4 years old, it makes feel really sad," says Ruby.
The wider Pirongia community has also come together to help the family out with meals.
"Isla's mum is up at the hospital with her and her dad has been here looking after her siblings. So to save them from having to think about dinner each night there's been a roster done by Playcentre parents, the PTA and the school," says Ruth.
The dinner meals get left in a chilly bin at the front door of the family's home.
The girl's fundraiser will also earn them their community service badge from their rally group.
"We'll be supporting our friend while trying to get our badge," says Amy.