Generally unlikely to be cost effective.
depending on where the hole is you'd probably have to remove the exhaust section, cut away to good metal, fabricate a patch, weld it and put the exhaust back.
Workshop time is pretty expensive and it would almost certainly be cheaper just to replace the exhaust section especially on a relatively cheap car.
Incidently it's quite outrageous that cars aren't routinely fitted with stainless steel exhausts it would add a really small amount to the cost of the car and I've had mine on my MGB for over 10 years and 100,000 miles now