War Cast Studio has made some new wooden barrel terrain pieces and have them available for sale now on their website.
From the announcement:
New wooden barrels are now available for 28mm tabletop games. Finely sculpted and cast in plastic, there are 5 large barrels and 5 smaller keg sized barrels in each set. Retailing at $5.95, you can now affordably outfit your gaming table with more detail and cover to hide your brigands behind. Perfect for pirate skirmishes, dungeon crawling, or city environments.