I have only purchased from my local dealer. She has sales often and I bought them one-by-one as needed for projects. They are all stored in a small plastic case with dividers I labeled.
Love the new machine that came with a case and many feet included. Lucky they all mix with each other.
I have placed orders for other supplies from here with good customer service and shipping.
https://www.sewingpartsonline.com/babylock-blty-unity-sewing-machine-parts.aspx#filter
type_gmcfeed_1:$2520Presser$252 0Feet