If you sell anything over at ThePit, make sure you figure in the fact they wont pay you for shipping. That is on your dime.
On Naxcom you will be flooded with lowball offers on your stuff. You can adjust the filter so that only offers above a certain percentage of your listed price will be sent to you.
On the terms of sales, I dont know, I only have Baseball. Looks like Football is doing well there right now.
Unless you have a free way, or atleast a cheap way to ship, you will just break even on shipping, selling on Naxcom. If I didnt get burned every 1 out of 5 transactions on Ebay Id stay there and sell....