In the Piggy Swap it's not a one to one trade. You offer your seeds, whatever amount and you choose your seeds from others, whatever amount Ella limited the "oinks" to. So, if you pick 30 different seeds you would like, you "oink" for them, even if only ten people "oink" for your seeds.
I think the Piggy Swap is more about people wanting to share what they have and would like to try some of what others have so it's not an even one to one. There are lots of people who offer a huge list of seeds and hardly ask for any. So in that respect it may not be for some who expect something in return for what they are putting out there.
