depends what season you're in really, if you're in the first, i'd say martin palermo from boca for 2mil (ish) he's a golden oldie and scored over 20 goals for me in his first season, with man city; and got 17 in EURO, i got Julio Cruz too, as I wanted to develop the rest of the team first and he was ok, got him for 600k, not as good but still did the job. I dunno what you're looking for or where you're at in terms of seasons, so maybe you could help me out there?
My bro recommends Owen, but what does he know (its a good choice, but i said nothing )