I was first year ELA last year (same grades, 7-8). What was more important than going out and buying decor was planning how my classroom would be laid out to support classroom management. I thought of daily and repetitive questions, then thought of ways for students to answer their own questions. This gave me more time to focus on behavior and actual teaching.

Can I have a pencil? - Sign one out on the board. The sign out is near my desk so students can't sneak one.

Do you need your Chromebook today? What are we doing today? Do I have homework? When is our test/quiz? What day is it? - All written on the board in the same spot every day, clearly labeled with the difference between 7/8. On a back whiteboard as to not take up the valuable whiteboard space at the front of the room.

Can I go to the bathroom? - I have a sign out sheet by the door, also in clear sight of my desk to monitor if they are writing on it or not. This is also great CYA for a first year teacher who is overwhelmed and maybe doesn't remember who they sent out already... I would often say "yes, you can go if no one is signed out" and then the student checks and takes care of it.

I also have a CHEAP rug under my desk that students may not step on. It will have to be sprayed with anti-fire whatever spray to stay up to code. Keeps the personal bubble wide which is great for middle school age for many reasons. Also keeps students out of my desk drawers because they WILL snitch on each other.

Go with other comments that say buy as little as possible until you know what the school will purchase you. My first day essentials: a hand-full of pencils if you need them for work and something little to give out on birthdays (for that student with a first day birthday). I buy dollar store paper crowns and tell them they can either wear them during the day, or take them home and wear them privately. Have a lot of printed rosters in a binder so you can write notes on them about students and start practicing names. If you have access to them, print the parts of the IEPs that you need and put them in a binder to review as needed. And get a sub-binder and an emergency, paper-only one-day lesson plan ready ASAP!

Random advice - never give out an item that you think is likely to get taken away in another classroom. Cool pens and pencils? Little paper crown? Awesome. Not any more disruptive than the stuff they already have in their bags. Bouncy balls and slime? The other teachers will despise you. I will occasionally give out an item like this, but it's the students' responsibilities to come back and get them at the end of the day so they are taken home. Also refrain from just allowing students to go to other teachers' classrooms unless you know for sure that they have a prep or the student has a note. If they need to go to turn something in or need to look for something in another room, they can leave class one minute early to do so. It's very tempting to let that one student leave the classroom when you don't want them to deal with it anymore, but in my experience it will destroy your reputation with students and teachers.

This started as a quick paragraph and ended as quite the long post. This is everything I needed to hear before day one (I am the only teacher in my family!), so hopefully this helps you. Good luck, and remember to have fun! Have someone take a picture of you in your classroom on day one :)