Does it have sentimental value? if so that is worth more than some saving by buying new.
I don't have a cost estimate for you, I just know that my mother had a couch that belonged to my grandmother, it was redone once just because it was gmas...Unfortunatly I didn't have room for it when it came time to do again, so I think the couch was tossed
.
Also, redoing the covering may not be enough, my MIL recovered her couch, and it well, never sat right..the cushions were all too short for the couch, and they twisted..it was weird, and annoying, while I hate my current couch, I can at least go weeks without readjusting, as opposed to redoing it every day! sometimes twice a day, ugh I hated that one.