I've already covered sending us resumes, papers, and abstracts in a past entry (tl;dr we do not accept these items) and today I want to cover a different kind of supplement. The expensive ones.
Every year, we get beautifully packaged submissions from students who want us to see pictures, certificates, art, and newspaper clippings. The use pretty folders, binders, and, in some cases, professional bindery services to present these items. They come in express envelopes or were dropped off by DHL/FedEx/UPS. It's clear that the students spent a bit of money on all this.
Everything that doesn't fit one of the categories of application credentials (transcript, recommendations, school profiles) goes into a bin labeled "Extra materials." Theses items are not reviewed by the deans. It's pretty time consuming to holistically review 30,000 applications. It takes us several months. We won't have time to include the books and binders in the review.
Please don't feel pressured to spend money on this kind of thing. The Common App is exactly what we need! Once you've completed your Common App, turn your energy back to the other things on your very full plate.