You should try to get Tony Watt. Bought him the first season in january for around 4 million and in one year he became the european wonderboy of the year. Scored around 35 goals in 45 matches and he is only 19
A good buy would be Nicklas Helenius, can get him for under 2mil and will score you 25+ goals a season if you use him effectively. When i did a Swansea save he became an Icon in the first season, and premier league top goal scorer.