I use amazon's mp3 store. The website has my credit card details and charges the card with each purchase. Amazon provide several ways of downloading the music, depending on what devices you use. I have an android phone. Amazon have an app that allows downloads direct to the phone (best over wireless). However, unless you back up your phone you could loose the phone and the music. I am not sure amazon would give you replacement files. So I prefer to download it to my pc (a mac in my case) and then copy it to the phone. There are many ways to copy files from a PC to a phone, depending on which type of each of each you have.