A post on ConversionXL sums up a bunch of experiments on pricing and suggests ways of combining them to best effect. All electronic goods can be had for free, so every person who buys an electronic good is essentially entering into a voluntary transaction. Getting pricing right is the best way to convince (rather than coerce) customers to pay, and to frame that payment so that it's as large as possible.
Researches found that sale price markers (with the old price mentioned) were more powerful than mere prices ending with the number nine. In the following split test, the left one won:
9 not so magical after all? Not so fast!
Then they they split tested the winner above with a similar tag, but which had $39 instead of $40:
This had the strongest effect of all.
I’m wondering whether the effect of this price tag could be increased by reducing the font size of $39. Say what?
Marketing professors at Clark University and The University of Connecticut found that consumers perceive sale prices to be a better value when the price is written in a small font rather than a large, bold typeface. In our minds, physical magnitude is related to numerical magnitude.