Engine noise E12 sounds clattering, racing, shabbling

Hello dear Corolla Kenner, I would like to buy a Corolla e12 te he has 115.00km down year 2003 and is supposed to cost 4700€, otherwise he seems to be in good condition, only a strange noise in the engine area makes me nervous, it is continuously not only when starting or couple and sounds folding, racingly shabbling, tinning. The seller says he has been driving with it for 6 years, was already with Toyota who said it was probably his valves that are loose or something and would be 3 00€ cost, it’s horrible but probably not the driver’s sleep so he didn’t read it, can someone help me??? Want this car! But not with a funny noise in the engine!