If you decide to use Xero you may also check inventory control system DEAR Inventory at dearsystems.com . It Integrates with Xero and eBay and helps you with stock maintenance. You can  list your items from dearsystem and every sale on eBay will automatically reduce available stock Level in inventory control system. By the end of each day all your ebay sales will be copied to Xero giving your accurate profit&loss position. DEAR Inventory also integrates with Magento front shop. You can sell your items on ebay and your online shop