This week’s US PlayStation Plus update offers a free copy of PopCap’s charming tower defence effort, Plants vs Zombies. That’s it for free content, but there are a number of hefty discounts. Retro/grade and its soundtrack are both available on the cheap, and Sony is discounting all winners of its annual Gamers’ Choice Awards, the results of which will be announced tomorrow. Finally, the Vita is about to have its first birthday so a number of games are going on sale. Visit the PlayStation Blog for all details.