Nokia 6255i / 6256i

hey im considering buying the nokia 6255i. I just have a few questions that i hope can be answered about it. i dont really kno much about mp3 players...all i kno is that you can download songs and it can go on the phone..exactly how many songs does it hold? and does it cost extra or anything to use this service? and also, i was thinking..wouldnt it like run the battery down to use the mp3 player? i just wanted to kno these few things before i purchased the phone..thanks 😁