So my kids collected a load of fir cones to sell on eBay, posted them and used the estimated price it suggested. They have sold like hot cakes! Couldn't believe our luck until we took them to the post office, only to find they are small parcel sized, which means we are effectively selling them for nothing!
I am obviously going to have to cover the costs for the dc so that they make their money, but I am furious with myself for not checking this first!