How much does it cost to change a camshaft for a 94 holden barina?

Just wondering if anyone knows how much it would roughly cost to have the camshaft replaced in a 94 holden barina. Do you think its worth it? Or should the engine just be replaced?How much does it cost to change a camshaft for a 94 holden barina?I just wonder how many other parts are about to fail? Made in Spain By Opel. The little Holden may have seen its better days unless you can find a good used engine from a wrecked car.