The indie online music store that describes itself as the “first digital music store propelled by social networking” received an undisclosed amount of Series A financing led by Amazon.com.

AmieStreet is not your usual online music store. First off, anyone – from the local garage band down the street to the latest indie fav – can upload their music. Then, instead of setting prices for tracks in its inventory, AmieStreet prices each non-DRM MP3 song free of charge, and then increases the price as more people download the tune, until the price reaches the store’s ceiling of 98 cents.

AmieStreet refers to its way of doing things as the Recommending system, or REC system for short. Founded in spring 2006 by three Brown University seniors, AmieStreet’s REC system allows users to “invest” in songs.

If a person is the first to recommend a new track priced at 0 cents, and if other users download the track thus driving up the price, the person who first recommended the track receives credit toward future song purchases.

In other words, you have a community of users not only interested in purchasing new music, but discovering and recommending new tracks as well. Is it any wonder it caught Amazon’s attention?

“AmieStreet has a very smart and innovative team,” said Amazon senior VP for business development Jeff Blackburn. “The idea of having customers directly influence the price of songs is an interesting and novel approach to selling digital music.”