items.forEach(function(item) {
  if(!isPurchased)
    saveToDb(item)
}

function notPurchased(advert) {
  return new Promise(
      function(resolve, reject) {
        if (description.length == 0)
          resolve();

        return request('adverts', {'count' : 50},  function(resp) {

          for (i = 0; i < resp.count; i++) {

            if(resp.response.items[i].text.match('purchased') != null)
              reject('This item has been purchased!');
          }

          resolve();
        });
      });
}

response.items.forEach(function(item) {
   notPurchased(item).then(function() {
     DB.storeItem(item);
   });
});