At this point, I'm trying to diagnose what the.

At this point, i'm trying to diagnose what the problem most likely is, so that I can make a decision about whether to fix the vehicle or get another. The engine is consuming oil at a quick rate. Roughly a quart every couple of days. I found oil on the underside of the frame rail, concentrated mostly at the point where you would pick up the front end of the car. There is a large rubber donut there and it looks like a place where either the tranny or the engine is mounted to. This is on the drivers side, and the frame rail is coated in oil as well. I found oil in the cooling system and reservoir tank. There is no coolant found in the oil. When the engine is warm and running, and the radiator cap off, bubbles are found coming to the top of the radiator. The intake manifold and head gaskets were replaced within the last 3-4 years. The engine runs well, does not overheat and the interior heat is ok. A friend has said that he thinks I have a cracked cylinder head. Others think it is a head gasket. Well, unfortunately, the difference in price for each of these repairs is enough to scrap the car if its a cracked head. I need some guidance here on what to do next. Are there any tests that can be performed to determine where the problem is?

Thanks!
Mike