A few quick searches on Amazon for those who are not familiar with the wealth of cheap classical music they have available in mp3 form. Everything below is in the sub $3 range, most at $0.99. Note that these same sets may also be on Google play or iTunes, but the price may be higher. However, if you find something you like, but don’t like dealing with Amazon, it may be worth a search.
If you do purchase through Amazon, you can download drm free mp3s from the orders page in your account, or using Amazon Music’s desktop app.
Bach Guild seems to be the best of the bunch, with some of the largest sets, and an eye to including complete works (including the entire symphony instead of just select movements, for example), but tend to be limited to a handful of popular composers. Cobra Entertainment’s offerings are where you want to look if you want one of those "Classical for Reading" or "Classical for Relaxation" type sets, they have a number of them, but Dream Collection and x5 music group have a few as well.
- Bach Guild – Big Box, Little Big Box sets
- Cobra Entertainment LLC – 100 Must-Have, Red Classics, Classic Care, All you Need is Classics sets
- Dream Collection – 100 Famous songs sets
- X5 Music Group – 111 Amazing, Rise of the Masters, 99 Most Essential, Top 10 sets