it depends what your old engine needs you need to strip it down and have a look

re plate of cylinders are about £100 each

pistons are about £100 for the pair

crank if it needs a rebuild/can be rebuilt £400

plus oil,seals,gaskets,coolant the list goes on

i have just stripped my 3ma tzr it was stood for 10 years and found the barrels to be fine but the crank seals had gone in the centre of the crankshaft
the whole rebuild cost me about £600