Wash their old backpack.
Unless it's broken beyond repair, last year's backpack can live to see another grade. Throw it in the washing machine and it'll probably come out looking as good as new. (Bonus: You've just saved a backpack from a landfill!)
Check the cabinets.
Before you go shopping, take stock of what supplies you already have leftover from last year. And schools sometimes send home the extras at the end of the year, so your kid might have a stash of pencils or crayons sitting at the bottom of their backpack. (You'll need to take those out before washing it, anyway.)
Buy in bulk and split the cost.
Usually the more you buy, the more you save per item, so team up with friends or neighbors to buy mega packs of basics like pencils, markers, folders, and tissues or wipes. Have a friend with a Costco or Sam's Club membership? Even better.
Trade or go secondhand.
This is especially useful for clothes and shoes, because we all know kids go through sizes at an alarming pace. Check your local Buy Nothing group on Facebook if you have one, or organize a swap event with friends or neighbors. And don't forget secondhand shops like Savers and Goodwill, where you can often find stuff in great condition at amazing prices.
Check the dollar store.
Never underestimate the power of your local dollar store. If you haven't been in a while, you'll be pleasantly surprised by the great deals on fresh notebooks, pens, and other supplies.
Set your budget and stick to it.
Consider this a math lesson for your kid. And if they desperately want something that isn't in the budget—well, sounds like it's time for them to get a job.