Well, the boring is worst case. The pistons might be fine. So it could just need new valves, head gasket, and seats recut, valve stem seals. How many miles on it?
Your only options if the pistons are buggered is, first over pistons, rings, bore and base gasket.
The valves are bent. You need 4 new ones, and the seats cut to them. Thats it. Maybe valve guides if they are worn. Or, you find used head that good...or another engine. There is no super cheap fix for this.