The knee bar is worth $30 by itself - though I doubt it goes with this machine (it looks like Singer). Come to think of it, I don't think I've seen anything other than Singers with knee bars for the cases like that. . .
This is a badged White machine, so it takes White bobbins, and White top clamp attachments. White took control of Domestic in the 20's, and after that "Domestic" because a badge name for White.