My DC are a lot older, so they make their own fun. They went away, but took advantage of the free things to do.
I guess as a result of this summer, next year you will budget to make sure you're not in the same place.
A good thing is to look at things you can do that cost nothing but maybe an ice cream, parks, reservoirs, nature reserves, other free places of interest.
They'll develop hobbies so they can entertain themselves better.
Uniform wise it's all Supermarket stuff, saved up for in a jar. Pencil case wise they seem happy with what they have as I'm really into art, so they're forever adding to their collection from mine.
Big purchases like coats, won't be considered till October time. We long gave up on Clarks as the wear is the same, so go to Brantanos.
I remember the days of the catalogue, when your Mum would get a mammoth parcel, with what looked like a school wear shop in. I know some schools now insist on blazers. So again something to save for. But as for jumpers with the badge on, they have 1 for photo days, then rest of the time it's £4 cheapy ones from Supermarket.
You can either save & buy in bulk or buy as you go along.
Sorry things are tight, if money is tight and you get say tax credits, uniform vouchers exist which help. Or used to exist. Make sure you get your milk tokens that can be used for fruit/veg.
Hope this helped.