Pretty sure vol. 1-4 are $9.96 at walmart(in-store)
BestBuy
Vol 5
http://www.bestbuy.com/site/Avengers%3A+Earth'S+Mightiest+Heroes+5+(2+Disc)+-+DVD/6581961.p?id=2511924&skuId=6581961&st=avenger earths mightiest heroes&lp=2&cp=1
Vol 6
http://www.bestbuy.com/site/Earth'S...7343084.p?id=2629528&skuId=7343084&st=avenger earths mightiest heroes&lp=1&cp=1
Amazon
Vol 5
http://www.amazon.com/Avengers-Eart...5829&sr=8-4&keywords=earth's+mightiest+heroes
Vol 6
http://www.amazon.com/Marvel-The-Av...5829&sr=8-3&keywords=earth's+mightiest+heroes
BestBuy
Vol 5
http://www.bestbuy.com/site/Avengers%3A+Earth'S+Mightiest+Heroes+5+(2+Disc)+-+DVD/6581961.p?id=2511924&skuId=6581961&st=avenger earths mightiest heroes&lp=2&cp=1
Vol 6
http://www.bestbuy.com/site/Earth'S...7343084.p?id=2629528&skuId=7343084&st=avenger earths mightiest heroes&lp=1&cp=1
Amazon
Vol 5
http://www.amazon.com/Avengers-Eart...5829&sr=8-4&keywords=earth's+mightiest+heroes
Vol 6
http://www.amazon.com/Marvel-The-Av...5829&sr=8-3&keywords=earth's+mightiest+heroes