check in selling manager

but you should have been keeping records all year, every month you sales, how much you've collected and then paid out for postage / stationery, ink, packingmaterials etc.

how much your paypal fees and ebay fees and bank charges were etc.

cost of initial stock / amount of stock left at eofy etc.

your accountant should have set all that up for you when you started yr little ebay business.

keeping track of it all either on a spreadsheet on your computer or at least in a note book makes it easier (and cheaper) once you get around to lodging your return.