When I started Secondary school in the early 1960s my uniform was only available from the Co-Op so my Mum saved up her 'Divi' through the year which helped with the cost. I have to say it was excellent quality: a wool blazer; heavy warm raincoat for the winter; and well made skirts, shirts and summer dresses. My GM altered my blazer and skirts each year so that they lasted more than one year. I was always very proud of my uniform and still have my tie and scarf.
Two of my GC started new schools this week, one to Secondary school and the other to Primary Pre-School. They both had to have full uniform, some of it from the school shop but some could be bought anywhere as long as it's the right colour. They both looked very smart on their first days.
I think school uniform is a good idea. When I have visited schools where uniform is not worn you are often greeted by a cacophony of colours and styles often inappropriate for school. A smart uniform reduces fashion competition, and promotes pride and unity in the school. But it should be affordable. School badges and logos can be iron-on or sew-on to reduce costs and allow parents to buy jumpers, sweatshirts and jackets from High street stores.
As for exercise books and similar materials, they should be provided by the school at no cost to the parents. I know exactly how much schools pay for these items from suppliers and it is a fraction of the prices in the shops. Now that parents are expected to provide tablets, laptops and other high value learning resources, as well as overseas educational trips, the least the school can do is provide basic materials.