An online music purchasing system and method is disclosed, in which a radio service operates on a user's computer and is configured for receiving and playing digital radio representations of media content in near real-time in a radio session. A content server is configured for serving the digital radio representations of media content to the radio service, and a radio sequence server is configured for serving a sequential list of currently-playing and previously-played media content of the radio session to the radio service. An account server is configured for receiving a signal indicative of a user's desire to purchase a file of one of a currently-playing or previously-played media content. A download manager is configured for downloading the file to the user's computer according to the signal indicative of the user's desire to purchase the file.