My senior can't figure out what good a $100 scholarship will do him.
I'm going to offer the alternate viewpoint here, thinking back to when I was a senior looking into financial aid, scholarships and the like (some 11 years ago now). Depending on what exactly is involved with applying for a $100 scholarship, I'm inclined to very quickly agree with your senior.
Sounds odd? Maybe, but consider the numbers a bit; and I hope this doesn't come across as overly cynical, as it's definitely not how I intend it. Consider how many scholarship applications require writing an essay, seeking letters of recommendation, etc. Take a guess how much time from start to finish goes into one... 3-4 hours maybe?
Now, consider the scope of various scholarships. Some are local, perhaps offered by a small business in the area, or something of the like. Others, like a fairly well known one that was offered by Coca Cola (not sure if it still is), have a national reach. That in mind, think about how many seniors are potentially eligible for any of these given scholarships, and of them, how many actually might apply. Now, think about how likely any given applicant is to be awarded said scholarship. One can do their own math here based upon assumptions unique to the situation, but as a gut feeling, most of these type of scholarships probably afford even an above-average student less than a 1 in 100 chance of winning it (and even that is probably high).
So, suppose we're talking about spending 3 hours to apply for a $1,000 scholarship that someone has a 1 in 100 chance of winning. Long story made short, in the long run, they'd be better off spending that same 3 hours working a minimum wage job.
That said, I don't mean to imply that there don't exist good scholarship opportunities out there, but you have to find the right ones. Some, like the Westinghouse award, offer as much as $100,000 for the winning individual or team, for a science/mathematics project or research. But in the same spirit of "finding the right one", you have to be particularly skilled in these disciplines to even stand a chance.
Now that I've babbled a bit, I'll just offer what I ultimately found to be accurate about financial aid. (I'll also mentioned that I left college in my second semester, never to return, but that is a different story) Most schools with a decent financial aid office, especially the more prestigious schools, will work very hard to help you figure out the financial stuff once you have been accepted. It will probably involve some combination of scholarships, grants, work-study programs, loans, and even some immediate out of pocket expenditure. But again, I believe they do work very hard to help you make it work. On the other hand, one can spend eternity going to "college is affordable" seminars, searching on web sites, and looking for some form or application that will completely take care of the cost, and will probably end up empty handed and jaded.