To transfer large files, most people use services like Dropbox.com or Wetransfer.com. Both of those services can offer you up to 2GB of free space. However, if you use a Windows computer you can have up to 1TB of usable space. Navigate to https://onedrive.com. There, you will see files on your computer that you can share if you like.
Simply upload your music file to onedrive.com and share your .mp3 30 Minute Mix music files with firstname.lastname@example.org