Ask HN: How to furnish our startup office for $500 total?

We have a 14.8ft (4.5m) square room that the three of us will share. Three sides are floor to ceiling smooth (metal) walls and the other side is all window. Other than office chairs and a couch how would you furnish this space in a creative way with a $500 budget. Any ideas will be much appreciated. We have an IKEA nearby.