I didn't know where to post this. I'm not selling here so that's why I didn't choose Classified!

I never know how to figure out fair prices for used furniture etc. We bought a futon for $225 when I was pregnant thinking we’d use it for guests when the baby was first born. It was used once! It’s sitting in the play area and holds my laundry basket and random things. What would be a fair price to sell it?