As explained on their Web site,
Seedlings Braille Books for Children is a 501(c)3 non-profit, tax-exempt organization dedicated to increasing the opportunity for literacy by providing high quality, low cost braille books for children.
I absolutely love Seedlings, and I can personally attest that they are fulfilling their mission: much of our twin-vision library has come from their bookshelves. One of the major ways that Seedlings promotes braille literacy is through its Book Angel program: each year, blind and vision-impaired children in the U.S. and Canada can receive two books from Seedlings’ catalog for the low low cost of free. Yes, free. You can register for the program at their Web site: http://www.seedlings.org/bkangel2009.php