Looking for books

Hi, I'm an italian teacher and I'm looking for the most diffused science and chemistry books used in your nation or at least, your area. In Italy there are few books very good and widely adopted by teachers. Is it so also in your nations? I would like to collect some of these widespread adopted science books for high school students or k9-k12.
I would be glad to those who could sell me used books or at least that can give me any title suggestion to buy using ebay.
I can pay expedition and used books with paypal
thank you for help
Bye
fabrizio reina