We had certain items that were brand specific- we had to buy Crayola crayons (for 40 cents a box at Target) and Fiskars scissors (for $1 at Target) but other things could be generic, which is why when it called for a 24-count of number 2 pencils, I spent $3 on the 72-pack at Office Depot and figured we'd have them for awhile.
Yeah, 22 post-it note pads seems excessive, but if she's sending home notes on them, sure. We also had to supply a box of Ziploc bags. I assume that's for sending home craft projects.
The supply list is standardized across the district. I'm impressed that we haven't received a "Yeah, but I also need..." note. Maybe they aren't allowed to send those.