The classic example of false pricing must be Finish Dishwasher tablets. Since they came out - around fifteen years ago - we've never bought a pack at more than 'half-price'.
The other example that springs to mind are the 1kg tins of Quality Street, Roses and Celebrations. They first appear in September, or thereabouts, at £11.00 per tin. No one buys, them, because they know the price will halve within a couple of weeks.