is sponsoring a special feature every Saturday morning that asks listeners to vote to decide which of three tracks should be the station's song of the week.
Listeners can respond either by text or online, and the incentive is the chance to win a 3 mobile phone and money to spend with 3MusicStore.
Galaxy has also created and will run 30-second ads in the style of the station's editorial content which showcase tracks that "3MusicStore recommends".
Galaxy broadcasts on FM and DAB in the North West, North East, Yorkshire and West Midlands, on DAB only in London, Leicester, Nottingham and central Scotland, and across Britain on satellite, cable and internet.
3's media agency MindShare has also booked similar exposure with other radio stations.
3MusicStore retails around half-a-million "dual downloads" for mobiles and PCs at 99p each.
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