“When selling low value items you have to weigh up the risk of sending items with no tracking” and “To send every item with tracking for PayPal protection would mean increasing your postage price or unit price, potentially losing sales”.   As previously stated all satchels and parcels now come with tracking.  So where is the extra cost?

The OP's items are obviously being post at Large Letter rate. To get tracking they would have to be sent either as Registered or at Parcel rate.