Occasionally you'll see a "collection" that is all the machines from a former service/repair store, which could not be repaired. In other words, they all had a serious enough problem it wasn't worth it to the owner to pay the diagnosis fee to get them back. Or they just let the repair place have them rather than dispose of the machine themselves.Walk away. She will be in touch again after the collection has been sitting there for months unsold.
I would also be very careful paying out that kind of money for a collection unless I saw everything in person and opened up every machine - how do you know half of them are not PRAM battery disasters or have other major problems?