I'm still teaching summer school, but summer school is only for grades K-3. Our 5th grade is moving to a middle school next year, and we will likely be adding sections in the primary grades, so a lot of people are moving classrooms. I have discovered that a LOT of people are going through their closets and throwing out things they don't need, and it is glorious.
GLORIOUS, I tell you.
My old co-teacher has been extremely generous- while she's at school for summer school, she's been slowly working through her cabinets and she found lots of things she never uses, like number lines and morning meeting posters and laminated charts- some not even opened- and gave them to me. She also found a huge box of books from an old reading series, and gave them to me. I found an old science series (we don't even use science series in primary grades anymore!) and a desktop file holder in the teachers' supply room. I found some thick cardboard mailboxes out in the hallway, about to be thrown away. I found binders and a few old board games outside a room where someone is moving.
I am so lucky to be in the school for the first part of the summer to see when people throw things out like this! I likely won't have my own room this year, so my "for a classroom" collection is collecting dust in the closet- but when the time comes, I'll have a lot more to start with.
Make sure if you have work to do at school over the summer that you walk around the building looking for free boxes! Plus, if your grade-level teachers know you're looking to build up your classroom, they will hopefully offer you first dibs. I've been VERY lucky and it's exciting! :) And better yet- FREE!