Viru Keskus is one of the smaller, but most centrally located shopping centers of Tallinn. You can find a good range of shops and boutiques which offer good quality for normal prices. Don’t expect very low prices though. For those, you’re better of visiting shopping centers like Rocca Al Mare, Kristiine or Ülemiste, which are located a bit further away from the city center.
Find Viru Keskus information on their website.