Blog.com offers you the possibility to play your .mp3 files directly in your blog, using a nice integrated audio player. Keep in mind that it only works for .mp3 files, and for internal blog purposes only.
First, on the Add New Post window, click on the Add Audio icon.
If you’ve already uploaded the .mp3 file to your Library, select it in the Media Library tab and hit Insert into Post (alternatively, you can make the upload of a new file from your computer or from an URL in the correspondent tabs).
A link will be automatically generated, that will be appearing in your text editor, looking something like this:
If everything works fine, you’ll get the audio player on your post (instead of just a link to the file), just like the image below.
Now that you’ve finished experimenting with adding audio files to your posts, remember that you can always disable it and change the audio player appearance in a Settings sub-menu called Audio Player.