I opened the tiniest booth available at a local indoor flea market/antique mall here in town. It doesn't bring in much, but for a flat weekly rate of $15, (they take no additional commission) it works out well to clean the clutter out at home, sell stuff and recoup some of the cost it was purchased for, and make a bit of profit on the side. I have to visit it to move inventory around and replenish it with more odds & ends about once every week or two.
There is also a Flea Market at the County Fairgrounds once a month. A small booth rents for around $60 for 2 days, I think. I did it once, worked my tail off all weekend, and made to the penny....$60. So breaking even just wasn't worth the work and sweat! Now a friend, Roger, sells brand new Nascar and model car stuff at the County flea Market every month and will make $1000 - $2000 profit each time. For him, it is totally worth it. I think it depends what you are selling, time of year, etc. It is something to consider.
Read more ideas at www.CreativeMoneyMakers.com