In this tab: information on finding reviews, prizewinner information, sales, bestsellers, and reader response.
You can find prize information for chilren's books from the following sources:
Publisher's Weekly and The Bookman can be found freely available up through 1922 in HathiTrust. In Publisher's Weekly, look for an index at the beginning of the yearly volume to find references to the best seller lists. In The Bookman you may need to browse: the list is not necessarily labeled "best seller list" or something similar, so cannot be searched easily. Volumes from 1923-1990 need to be consulted in print in the Main Stacks.
In 1945 Alice Payne Hackett published Fifty Years of Best Sellers, 1895-1945. Available online through HathiTrust, it gives the top 10 sellers for each year based on Publisher's Weekly and The Bookman, with a narrative overview that gives more concrete numbers on sales. The first edition also has a very useful essay on the history of best seller lists. This book was updated every 10 years until the most recent edition, 80 Years of Best Sellers, 1895-1975 (print only), which has the introductions to each edition, and the yearly lists, as well as some additional useful features: total best sellers for this whole period split into paperback, hardback, and combined; and best sellers broken by subjects, including children's books selling 1 million or more copies by 1975.
Find more bibliographies of best sellers that may have sales information included with the "Best sellers -- Bibliography" subject heading in the library catalog.
Beyond the above, sales information for particular titles might be found in individual book trade news reports or research articles--however, those numbers and articles are again only likely to be available if the book was very popular (and thus likely on the best seller lists).
Individual reader responses can be difficult to locate, especially if you are looking for responses to a particular book. They are most likely to be found in things like diaries, letters, and other ephemeral publications that may only be published if someone well known wrote them.
The library catalog uses the subject term "Books and reading" to identiy books that are about people's experiences with books. There are many memoir-type books where the writers review books they have loved or that have shaped them that carry this heading.