If you're looking to sell for less than $40 or $50 then the forums are probably your best place. Marketplaces like GoDaddy have commission costs that really doesn't make it worth listing for that price. At least here at NP (and on some other forums) you don't have to pay anything.. It's perfect for closeout priced names!
+1 on the NP forums. Quick to sell, lots of views and no commissions.
I previously used GoDaddy but their latest commission increases and minimum pricing changes pretty much killed the quick flipping on sub $35 names. Also tried eBay a few times but it was more hassle than its worth.