Fellow Air Force personnel can download various audio books for learning Japanese for free here.
Air Force Digital Media Program - Search Results
NOTE THAT THIS IS COMPLETELY LEGAL, you just have to delete the files at the end of your lending period (and sharing for most files is forbidden, you will be given rules for each file). Contact your local Air Force base library and make an account, after which you will be given a code which can be used to log in. This is available for military dependants too.
The courses on here are hardly 'advanced' but might help begginers, although I'll say right now avoid "Dr. Blair's Japanese In No Time" it is mind-meltingly retarded, with some of the stupidest mnemonic devices I have ever heard D: "Eat the ducky moss" for "Itadakimasu" "Cone knee cheese wa" (Konnichiwa) etc.
By the way, does anyone know some good intermediate audio-only courses for learning Japanese? I have been searching high and low for a good audio course to listen to while I work but it seems like a lot of audio courses don't get very in-depth, and they call a lot of audio courses "Advanced" that aren't even lower-intermediate. Any recommendations for good audio-only courses that are truly intermediate to advanced?