Is mp3 better than wma?

Tweet

Is mp3 better than wma as far as sound quality? I just got an mp3 player and it says that it can hold 240 songs on mp3 and 480 on wma. Does this mean that wma sound quality is worse? Do mp3 songs and wma songs cost the same? Why can my mp3 player hold more wma songs than mp3 songs? If you could help that would be great!