Curious as to what shopping carts are available for print shops.

Prefer a cart that is open source "free or paid" and is owned not leased.

Some websites:
uprinting "dot"com
vistaprint "dot"com

online design editor is not as important as the qty, shipping etc the way it is outlined. Of course a design editor would be great to have.

Are there solutions out there already or would a custom shopping cart need to be developed?