For elementary school (my little cousin), I have to agree with Target & Walmart of inexpensive (ok to break or loose) type of supplies. And for more quality items (expect to last long with style), I would recommend Disney store and Pottery Barn Kids.

Pottery Barn Kids actually has a 20% Off Entire Purchase code right now too!
https://www.dealsplus.com/potterybarnkids-coupons?code=5446592

Walmart would be my choice.

Thanks @pandbear21,

I'll definitely check later this evening to see what they have. :)