Check the overall condition, no rust, flaking paint, gouges etc. Decals should be intact and bed should not be covered with scratches. The case shouldn't have mildew or smell moldy, the hinges shouldn't be broken and the accessory tray, attachments and manual should be included. Definitely check for the bobbin case as they are more than $50 in Canada. I've seen featherweights priced from $10 to $500 at garage sales although the price seems to have leveled off lately.