if you can get the serial # & model # from the machine you can look it up on the Pfaff site and get an idea about the machine- and also find out about attachments/bobbins- or call a local repair shop if there is one in your area- to see what it will cost to have it (gone over, cleaned and tuned up)
i would think the cabinet alone would be worth $25-$50
maybe just donate for the value of that- figuring the machine you will probably have to put money into to get it working.