It can get very messy, very quickly when you mix personal sales with business sales on the one selling account. It is always best to run a seperate selling ID for personal stuff.

Having said that, now that it is done, in answer to the first two issues, ( items sold for friends and neighbours ). One way might be to ask them for a purchase reciept equel to the price the items sold for, minus expenses. That way you can claim you purchased them for the same price you sold them, making them revenue neutral as far as tax is concerned. Its not perfect, but may be a workable answer for now.