Some stats on contributions to Hillary Clinton per the FEC filing of March 31, 2016.
The histogram above show the number of contributions by amount, $1 to $2700, in bins of $100. By far the largest number of contributions (over 300,000) were for $100 or less.
Some detail on the contributions of $100 or less, in bins of $1:
So the most common contribution amount is $25 (nearly 80,000 contributions in that amount). Interesting that people tend to give in multiples of $25. For the smallest donation amount above, the princely sum of $1, there were 2,116 contributions.
Total number of contributions listed in the filing: 440,672
Total contribution amount: $134 million
Average contribution amount: $304
Median contribution amount: $50