It can get even crazier than that ...
When I was going to grade school (in the 70s), you would receive the next year's school supply list with the final report card (so, last report card in 3rd grade, you'd get the supply list for 4th grade). Now, they might specify things like wide-rule vs college-rule, rounded-point scissors vs regular, and so on, but it was pretty much left up to you if you wanted one notebook in each shade of the rainbow, or some plain notebooks and pictures on others (puppies, kittens, favorite sports team logo), and the supplies were strictly one's own supplies.
The summer could be spent buying supplies a bit at a time, or you could wait till the end and just buy it all in one fell swoop. Several stores also had sealed up bags labeled "District X, Grade Y" for the districts in close vicinity, and those bags had just plain colored notebooks, none of the "cute" ones.
When I had my oldest in public school (which ended after first grade--I homeschooled after that until moving to another state), not only did it matter what school, but also which teacher--because the two teachers of 1st grade at the *same* school would have wildly different lists. And you couldn't get the lists until after the first day of school, at which point you had to run out and buy the ridiculously detailed supplies (you *must* have pocket folders in red and green and spiral notebooks in blue and orange. Do not even think about sending your child to school with pocket folders in red and blue and spiral notebooks in green and yellow). In the other classroom, they'd have required pocket folders in yellow, orange and black and a red spiral notebook. Teacher A might require 18 colors of crayons, but Teacher B insisted that only colored pencils would do. But they couldn't tell you in advance, because there might be changes to enrollment that would mean they'd need to swap kids around. Apparently the idea of standardizing the list between teachers under the same school roof for the same grade was too complicated.
What I wish they'd do now--and I see no reason why this couldn't be done--since the high school has a faculty page with each teacher's picture, why couldn't they put a link there which shows which classes the teacher is teaching and each of *those* links going to a supply list for the class. So if you are taking Ms Apple's English Literature class, Mr Banana's Accounting class, Mr Cherry's Geometry class, and Ms Diakon's Chemistry class, you'd have the lists for each of those and could make your shopping list accordingly if you liked to get things done ahead of time, or wait until classes and get the syllabus for each class to get the supply list and buy in a mad frenzy the evening after the first day of school.