New Frame needed

The body is the frame. If the damage is minor the unibody can be straightened.

A car that old is probably not worth fixing.

There is a front "frame" called the engine cradle. in the rear there is a rear suspension member. Depending if your problem is accident damage or rust you can get a used replacement.

It is rusted. Can I sell it for parts? What's a fair price?

If you have some place to park it and part it out, yes you could sell parts. You could also sell the entire car to someone with a similar Impala and they could use it for parts. Last, sell it for scrap...call a scrap yard and they will tell you what they will give....it will be so much per pound, steel prices are not that high.

Thank you for your help. I appreciate it.