A standard head gasket if i remember right it about 40/50 quid. when i got my head skimmed at halloween it cost me 35 quid. You will need a new inlet gasket as well just to be safe. You could buy new gaskets for the thermostat housing but i just used hermotite, does the job rightly.
Plus then the time and labour to do it, unless you do it urself.
Unless you take the engine out of the car the block cannot be skimmed. So if your geting the blocked skimmed you mite as well rebuild the whole engine as you have to take it completly to bits.
A cost on a standard rebuild.. how long is a piece of string basically? There is so many bits you could keep and could replace with new parts that a cost would be hard to say. Some people would stick a set of rings in with new gaskets and let it go. other would buy new pistons, rings, regrind valves, new oil pump etc etc
hard to say on the cost of a standard rebuild.
Jonny