Originally Posted by
KLouis
Look for hotels in the town of Fiumicino, there are a few. Ostia, a few km further south, is also a possibility. The rooms will be well under 100€/night. I know for sure that there is a bus between Ostia and the airport and there may well be one to/from Fiumicino too; otherwise, a taxi would bring your expenses way up again. I'm certain that you could check-in at the hotels around midnight but, just to make sure, call them before booking.
There are a couple of buses that go to the bus station drive-through at Fiumicino from the bus area outside terminal arrivals. However, the smaller white local "Trotta #8" bus (1 euro or 1.5 euro, per drivers) is boarded across the street and hedge at a stop just before crossing the one lane to the Leonardo train entrance (ground level, outside). Usually runs every 40 minutes (may be 1 hour on weekends). You can use the Moovit or Rome2Rio apps for timing, too. They also list the other companies that go through the arrivals area (blue bus, for example). Someone may have more specific info. There is a stop not only at the Fiumcino bus area, but also by the Mercure Hotel (a couple of blocks from Best Western) and around the corner on the sidestreeet (inbound to airport only) just before the Todis grocery store.