There are not a ton of free children’s classics for Kindle, but there are some good ones. I suppose the common theme here is copyright has expired. Here’s a sampling and here’s the link.
I do love a good Top 10 List and this chapter book children’s book list for ages 10-14 (middle-school-girl-ish-give-or-take-a-year-or-two) from ChristinaReads is a really good one with her childhood favorites!
Top 100: Children’s Novels from School Library Journal, grades 3-8th, for 2010. Great classics that have stood the test of time plus newly released Newbery award winners.