public function setCollection($collection)
{
    $this->_collection = $collection;
    $this->_collection->getSelect()->where("type_id = 'simple' AND price > 0");
    return $this;
}

public function getSize()
{
    if (is_null($this->_totalRecords)) {

        $sql = $this->getSelectCountSql();

        $this->_totalRecords = $this->getConnection()->fetchOne($sql, $this->_bindParams);

    }
    return intval($this->_totalRecords);
}