Dont forget ebay also charges you 13.9% of shipping as well as 13.9% of the sales tax they collect. I sold a fairly large expensive item a few months ago and the overall fees were close to 30%. Also, if you sell international and for some reason the customs delays the package and the customer does not pick it up on thime you will eat all the shipping and give the part away! Ebay will NOT refund your shipping cost. I am 100% done selling internationally after I had this happen to me.
Also, ebay throttles your listings so you can only sell a certain amount every month. It is absolutely not a place you can count on to have your items get seen. To get decent exposure you have to list pretty much every day and this turns it into a job except it is a job you never know when you can expect to get a payday from!
Bottom line is ebay is not the place to sell parts anymore