Think about this: if you sell low,you also buy low unless you are not going to buy a house ever again. I sold my house at $40k lose,but I also bought a house which I could not afford when I could sell my house with profit.
Also, depending on how long have you stayed at your current house, 30k~40K lose including agent fee really is not that much, you can deal with agent to let him/her be your buyer agent,then you may lower the agent commission about 1%.
Hire a good agent who knows more than you. My agent actually brought professional person and art staff to decorate my house before putting my house into market, it made me feel amazed "wah, is it my house? I should stay instead of selling it :D)", she also sent a professional photographer to make a nice vitual tour on website, really nice!! not mention open house, dealing with buyer agent.... sale by owner can only save about 3% as you'd better pay buyer agent at least 2%, and you get youself a lot of works to. it is, I think, just not money & energy costive way if the house market is buyer market instead of seller market.