That variable will vary depending on the town you are in and the services you need. Your true costs include: Realtor commissions, attorney fees, title insurance and other smaller fees. You also may need to pay for transfer stamps if your town requires it.
Depending on when you sell your condo, you will also need to prepay the property taxes for the next buyer. Assuming a sale in the 2nd half of the year, it would be at least 12 months worth of taxes.
When you meet with an agent to get a Comparative Market Analysis, let them know you would like a Selling Cost statement as well. They can estimate your costs based on a possible sale price and show you how the math works for your specific property.
Broker Baird & Warner