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Blast your tunes using the power of the sun at your next beach party by merging a small digital amplifier, a pair of El Cheapo bookshelf speakers, batteries, a small solar panel, and a fully loaded MP3 player.
The most expensive component is the digital amplifier-Instructables user pekar recommends snagging a Sonic Impact 5065 Gen 2 T-Amp, which runs around $60. The solar panel itself will cost around $10 to $15, so you could conceivably snap this together for under $75, especially if you cannibalize components from dead electronics. Oh, and you'll need to know your way around a soldering iron. ::Instructables
See also: ::Build a Solar-Powered Radio for Less Than $5 and ::Build a Passive Solar Water Heater
Difficulty level: Moderate
