The last time I saw a penquin foot selling on EBay (a couple of days ago), the last bid I saw was $249 USD. I didn't see what the final bid was. A penquin foot is not a name brand, it came from Singer and was named that because it was black and walked like a penquin when sewing.
Also, did they show what kind of card table it was? When the featherweights first came out, they had a card table like sewing table. They were made of wood with a drop in place for the machine. Those also goes for around $200 USD. Wow, you could have a veritable treasure trove on your hands. Good luck.