If you want to stay for a few days in Ostia, I can absolutely recommend Perla´s bnb. We didn´t expect that the breakfast was included, but it was and it was great! Perla served far more than it´s usual in Italy, beside sweet staff we got cheese, Salami, ham, tomatos and salad...juice, cafe latte and cacao :)
Though just having 1 room, it feels like having an own apartment as there is also a common room, a kitchen and this wonderful, spacious terrace with comfy chairs! The apartment is just in the center of Ostia, so you can not be more central! For us it was perfect to stay in Ostia at Perla´s place before heading back to Vienna. BTW there is a bus from Ostia train-station to the airport (ca. 20 minutes) for 1,50€!
Perla also answered to all our questions immediately and gave us useful tipps. Thanks again!