Hey TR I got a 1986 Chevy S-10 Tahoe.....and the pics will do the talking

And to prevent from the rust from spreading (i heard that rust could spread throughout the car!?)

So i decided to cover it up with duck tape to prevent any harm to it....
My question is the duck tape a good idea to prevent any more damage to it until i get it fixed?
and how much approximately to repair it with just primer paint cause the paint is already dead.
THANKS