You looking for a first team player or young one for the future?
First team look at: Costa, martinez, Rondon, Falcao (depends on price), perhaps balotelli but can be inconsistent depending on saves.
youth look at: zivkovic as said above, Batshauyi, destro or perhaps Volland
Need a poacher that will guarantee me goals? 45M to spend
Playing 4-2-3-1