You can order a box of books from this site for $12.99. They will range from toddler to young adult books. Each box contains approximately 150 books (give or take). You can also order more age/grade specific books, but it costs a bit more. There is now an advisory on their site that due to high demand, boxes may not ship for up to 5 weeks, but for $12.99, that's a small price to pay :)
103 things all SF kids should do in the city
"The Crock-Pot Lunch Crock ($20) makes us so very happy! We've got nothing against the breakroom microwave, per se, but warming our food slowly and safely on our desks yields much more flavorful lunches. Our pasta leftovers don't congeal and separate, soups warm thoroughly, and we don't have to wait in line to nuke."
Watch your veggies grow! (A great way to teach kids how vegetables grow).