I think you will find the number of people who collect $50 and $100 bills is very limited and those with the means to collect larger denominational notes tend to look for higher graded notes. These are not typically ones you can find in circulation.
Well, I'm not sure about that statement. I have in my collection all the small size $ 100. notes in all the series years from 1928 on up and there not all in UNC condition. I agree, not everyone can afford to collect them in UNC condition.
I know I cant, but I have built up the collection over time in less than UNC condition. The way I did it was to get what I could find at the banks, when I did buy I bought the best I could find that had good eye appeal, not UNC but still good looking notes.
You can find these sometimes for $ 10.00 or not much over $ 15.00 over face. I looked at it this way, most of the notes I bought were $ 20.00 or less over face, being that I was getting back my $ 100.00.
It was a good way for me to save some money and at the same time build a collection, the most I could lose would be the cost over face
So you see not everyone need be rich to build a nice collection, and not everyone needs to buy UNC notes to have a nice collection.
Yes, you will find that some cant afford to collect $ 50. or $ 100. notes, I'm sure there are guys that cant afford to collect $ 5.00 and $ 10.00 notes, but don't forget, it's not always about how much is it worth, it's called "collecting" not "investing", and if your collection ends up being a nice investment good for you, if not and you buy right you will have a lot of fun building your collection and the most you would lose would be your cost above the face value of the note. The Bill Collector