Noticed today that Scholastic’s 50 books for $50 promotion is back. Winter sale good through 2/28/17.
These are fantastic sets to supplement your elementary school-aged readers.
https://shop.scholastic
I ordered a couple of sets (K-2, 3-4) a couple of years ago, and am now adding to my collection (additional 3-4, 2 x 5-6). You’ll get a mixed bag of titles, but definitely worth the price.