It seems like organizing homeschool supplies and how we set up our spaces is a common theme so I thought I'd take a few minutes and post our space. This is (at least) the 4th different method we've had and it seems to be working the best (so far). We are renting so everything you see is mobile, nothing permanent and nothing adhered with anything more than nails or screws.
You will notice a lot of Ikea, because it's affordable and it works. None of the links below are affiliate links because this blog isn't a business. It's mostly just a way to keep my ideas organized and share homeschool plans with my husband.
Right now our calendar time board is in the kids' room. Most of our schooling takes place in our dining room but since we also entertain in that space we didn't want this on the wall in that room. This works okay, but ideally I'd separate it from their sleep/play space. They're easily distracted when we are in there.
Cork Boards*-
Jo-Ann
Calendar, numbers, and months - hand-me downs from my mother
Spanish months -
Mardel
Book holders -
spice racks from Ikea
*Cork boards are expensive and I am "frugal" so instead of buying a 4' board, I bought 2 smaller unframed cork boards on sale at Jo-Ann's (looks like they are currently on sale again). The cork is really thin and peeled easily so I covered them in a cheap neutral fabric from Wal-mart. The sticky pieces to adhere them to the wall didn't work and peeled off the drywall texture (at our old house) so it was better to just nail/screw through them into the wall.
For independent work time:
small "desks" -
side tables from Ikea
Little Tikes plastic chairs - consignment find
art easel* -
Ikea
*I wish it was magnetic so we could use it for magnetic numbers and letters. I think I'm going to add a magnetic board or cookie sheet to the wall for that instead.
Paw Patrol back drop is left over from her birthday party - totally not permanent. I got some large maps for free before I left teaching at my high school. They're nice enough to go up permanently but I'm waiting until we start our "new school year" in the Fall.
I totally stole this idea from Pinterest, and I love it a little too much. At one point I had two of these used in this manner in our house in addition to two in my kids' rooms for shoe storage. By the way, there's a cheaper version in-store at Wal-mart for about $5, or at least there used to be.
We also have a drawer for art supplies we use regularly in what looks like a sideboard in our dining area but actually serves to store my sewing/craft supplies. It's the stuff we use most often like crayons, paints, markers, colored pencils, and glue. For my mental health I really wanted it with everything else but it works really well being right next to the tables where work is done so I left it alone.
This is our main closet for homeschool storage and supplies. (I guess most people use it as a linen closet.) The clear bins and white buckets are organized by month/season or by subject. Each month I take out what we need from the appropriate bin/bucket and put it on our cart (shown below) or in our sensory bin for the month. Inside the month/season bin I include everything that is specific to that theme - like books, sensory bin supplies (in a large zip lock bag), and anything we do only in that month. For ongoing subject activities (like Math and Reading) I keep it grouped by subject.
This cart is how we honor my husband's request that the dining room table is still usable for meals. When we are done for the day we can load our things from the dining room table into it and roll it back to the closet. It also serves as a symbolic "start" and "end" to "school."
The bottom shelf holds the month's bin (except for the two seasons that are too big - Christmas and Valentine's). Since most of the supplies are set out in their "home" for the month (sensory bin items in that bin, books on the shelf, etc.) this bin now only holds extra activities and supplies that I know we need for specific activities or projects. The middle shelf holds workbooks, chalk boards, white boards - basically anything we write on. The top shelf has become a catch-all for the stuff that doesn't fit elsewhere but that we are using that week - a "junk drawer" of sorts that lets us clean up quickly.
Weekly supply storage -
Rolling Cart from Ikea 
Emphasized play and frequently read books. Animal bins hold toys for homeschool play in rotation - puppets, musical instruments, soft balls, etc. Free play toys are stored in their room. Yes, this is in my living room. And don't you love the picture frames I got for Christmas but have yet to fill?
Storage for unit studies, workbooks, leveled readers, teacher manuals, and unit studies. The magazine files hold books and activities by theme (insects, civics, reptiles, ocean). Within the magazine files the themes are separated by file folders.
Honestly, it was a fair amount of work to get everything sorted out this way but it was so worth it. I was so sick of knowing I had supplies or books but not knowing where. Or worse, completing forgetting what we had because it was buried in a box. So far keeping it this way has been easy because the kids are trained regularly to pick up what they get out. Also, they helped me organize the things that mattered to them (like their toys) and now they are pretty picky about where things "go."
