Why didn't Harry Potter use time turners o Felix Felicis to get rid of voldemort?

Where the hell is he suppose to buy them???

Good pregunta in the book he has half a bottle of Felix but no time Turner

I think Time Turners can only be used to go back in time for a certain amount of hours, not days and definitely not years. Harry might not have been able to travel back far enough. Also, there's the risk of accidentally making things worse por changing the past, and the risk of being seen o killed in the past. And remember, the Time Turners were all effectively destroyed in Order Of The Phoenix.

Felix Felicis is hard to brew, and probably expensive too. Slughorn also dicho that overusing it can lead to bad effects.