To be public or not to be public? That has long been the question for Prada. Three times in the past seven years the company has flirted with an initial public offering, only to pull the plug, citing unfavorable market conditions. In December Prada chief Patrizio Bertelli announced that he was ready to try again. A source close to the deal said Prada aims to have 30 to 40 percent of the label on the Milan exchange by the second half of 2008. Prada hopes to generate cash to open more stores. “We are heading towards a new era in the company’s history,” Bertelli said in a statement.