Not true! The Greeks do have a shortage of coinage, but, are just as likely to round prices down as up. Holidaying in Greece regularly, we've not found any significant price increases since the introduction of the Euro.
So how do you explain the consumer boycott in Greece today? Greece's consumer association seems to think prices have gone up as a result of retailers cashing in on the intriduction of the euros, and they were supported by the greek govt.