Hotel La Scaletta is a very nice place to stay. By US standards, it's pretty small (only 21 rooms), and the rooms are small as well. The rooms are comfortable though, the staff are friendly and speak English (can be very handy). It's across the street from the beach, a short walk to a stop on the Roma-Lido train line, and there are lots of food choices nearby to pick from.
Our room was on the side of the hotel with a long skinny balcony that ran out to the front with a very nice view of the Tyrrhenian Sea.
Although you're outside of Rome, it's pretty easy to get to. A short walk (~10-15 minute stroll) over to the Lido Centro station. and then ride the train to the Porto San Paolo/Piramide stop (at the very end) where you can transfer to a metro train that takes you further into Rome (you can also transfer to the metro train at two other stops before the end).
If you're looking for a nice, inexpensive place to stay in Rome, I highly recommend Hotel La Scaletta.