At our elementary school, supplies are presold with the quantities of everything requested. These supplies run from about $45 to $60, K-5th grade. Of course, no one is "required" to buy the presale packets but it does not make sense to me why not because you can't go to an office supply store and buy everything for the price of the presale items.
As far as distribution. Most everything is labeled with the child's name. EACH child has a pencil box with crayons, pencils, scissors, eraser.
The pencils that are brought in per child are put into labeled Ziploc bags for that child. The teacher will distribute pencils as needed from your specific bag.
Notebooks and folders are labeled and kept for each student.
The teacher also has extra paper which is "community" paper and used for spelling tests, etc.
Tissues, wipes and sanitizers are all combined and pulled out as needed.
At the end of the year, we are very low on tissues, wipes and sanitizer and usually the teacher steps up and purchases more with his/her own money.
Anything that was labeled and not used, is given back to the student. Other supplies left over (old markers, crayons, etc) are distributed to the children who want them. Workbooks provided by the school are sent home with children as well.
In all honesty, I've not seen many supplies ever be given back to the students because most everything is used up by March and has to be replenished. Some parents donate supplies needed to last until the end of the year.
It is strange on the community supplies to see how some parents want their box of tissues or wipes labeled as they are so afraid someone will cheat them somehow. There is one nationality that is known for this behavior.
Nothing is thrown away or wasted at our elementary schools. They try to forecast what is needed from each student so they don't have leftovers at the end of the year.
ETA: in Middle and High School it is different. EACH teacher has a list of supplies and to motivate the students to contribute, theyare given a positive daily grade if they do bring supplies. I fund it much more expensive in Middle and High School than elementary.