Concordia Publishing House’s set called, Martin Luther: Hymns, Ballads, Chants, Truth is available in MP3 download format at Amazon for only $5.49.
This set features 39 pieces composed by Luther, interspersed with some of his spoken quotes about the Divine gift of music to encourage our faith and express our worship. I bought this a few years ago and have enjoyed it immensely.
The blurb at CPH says:
This monumental recording project presents, for the first time, a complete recording of all the hymns, ballads, and chants composed or authored by Martin Luther. This four-CD set provides numerous vocal and instrumental settings combining Renaissance, Baroque, and modern instruments.The CD retails for $44.95 (on sale now for $34.95 unless I am mistaken), so this is a great deal. If you click the link above, you’ll be taken directly to Amazon’s page for this recording.
Many hymns are preceded by preludes composed by significant historic and contemporary composers. All texts are sung in English by a choral ensemble noted for vocal clarity. Historic narrative is provided, quoting Martin Luther concerning music, worship, and liturgy.
HT to the Internet Monk for pointing this out!