It's not quite as long as
I Love the 80s, Vol. 1, which I highlighted in January and which is still free, but
I Love the 70s (1770s & 1870s) still gives you an hour of good classical music to read by.
- Performers: Johannes Brahms, Antonin Dvorak, Edouard Lalo, Carl Stamitz, Takako Nishizaki, Polish National Radio Symphony Orchestra, Johann Baptist Vanhal, Donald Armstrong, Jeno Jando, Benjamin Godard, Antoni Wit, Bournemouth Symphony Orchestra, Jaroslav Krecek, Ilya Kaler, Bernd Glemser, Maria Kliegel, Franz Joseph Haydn, Stephen Gunzenhauser, New Zealand Chamber Orchestra, Slovak State Philharmonic Orchestra, Kosice, Toronto Chamber Orchestra, Pietari Inkinen, Kirk Trevor, Capella Istropolitana, Pyotr Ilyich Tchaikovsky, Wolfgang Amadeus Mozart, Christopher Hinterhuber, Carl Philipp Emanuel Bach, Kevin Mallon
- Composers: Pyotr Ilyich Tchaikovsky, Wolfgang Amadeus Mozart, Carl Stamitz, Franz Joseph Haydn, Carl Philipp Emanuel Bach, Antonin Dvorak, Edouard Lalo, Johannes Brahms, Johann Baptist Vanhal, Benjamin Godard
- Conductors: Jaroslav Krecek, Pietari Inkinen, Stephen Gunzenhauser, Kirk Trevor, Kevin Mallon, Donald Armstrong, Antoni Wit
Also free and classical, yet a little more modern, is
Decca & Deutsche Grammophon: The Con Brio Digital Sampler - Artists With Vigor And Spirit 
Not free, but bargain priced is
The 99 Most Essential Debussy Masterpieces, an Amazon exclusive and currently only
$5.00 as part of this month's
100/$5: 100 Albums for $5 Each
promotion at Amazon. A few others I noticed on that promotion that are worth checking out:
Back to free downloads, the
X5 Free Sampler - Blues and Country Legends is a short one, with five cuts from Lightnin' Hopkins, Muddy Waters, Hank Snow, Canned Heat,Woody Guthrie, but is well worth downloading.
The
Christian Music Sampler, by The O'Neill Brothers, is another long sampler at over an hour. If you prefer vocals to instrumentals, you might also want to check out some of these free singles:
A few more free samplers:
