Most likely that machine is filled with plastic gears and parts, as well as stamped sheet metal parts. It probably can be repaired, but ... would it be cost effective to do it?
Example: Wife and I picked up a Singer 3343C, a circa 1990 machine. It cost us less than the cams that came with it would have cost. (We wanted the cams, so the machine was just something to mess with.) It sews, but it's got a cracked cam drive gear.
I priced it out and the sources where I find this gear have it listed for nearly $80 dollars. 80 bucks for a cheap plastic gear. I told my wife to use it till it dies then we'll part it out. The cams and attachments that came with it are more than worth that price. But I will not spend that kind of money on a junkie plastic gear.
Like the others have said, look into it yourself, you might be able to fix it and then you'll have learned something.
Joe