Used literally in the context of competitions in which the prize is to run around a shop (for 3 minutes, say) and everything you can chuck in your trolly you keep. Now used as a metaphor for coarse, undignified consumerist greed.
'what Posh n'Becks typify about modern Britain is their working-class-made-good Trolly Dash mentality'
by bazworthy April 18, 2008