You will be well out of pocket, a 3kg satchel costs over $11 I think then there is the ebay final value fee and the Paypal fee to pay.

It may be a good idea to revise your listing anyway to correct where it says "very unique"? Something is either unique, that means there is only one of them, or it isn't. It is grammatically incorrect to qualify it in any way. You should either at least double your selling price or take off the free postage and charge whatever it is going to cost.