In April my husband, my in-laws and I stayed at B&B Ariosto for a couple of nights. It was our first time in Rome and I had been in charge of booking the accommodation. It's really hard to find a decent priced B&B in Rome and even harder to find a clean place (we also stayed at another place in a different part of town and it was a rip off and very dirty). B&B Ariosto was great and only 15 mins walk from the Colosseum. Super clean bathrooms (yes, there are 2 not 1) and big rooms. Breakfast wasn't great but that is because Italians don't eat breakfast. Besides there are so many places to stop and grab a bite to eat while walking around the city (which we LOVED). The hosts are really nice and helpful. They stored our luggage for the day once we had checked out. The place is very secure and safe.
The downsides: it's hard to find (from the Colosseum direction make a left onto Via Ariosto and it's the first apartment building on the right - you need to check the buzzer for B&B Ariosto as there are no signs) and the top blanket on our beds (there was no top sheet) was dirty from previous guests (I'm sure if it bothers people they will give you another sheet...).
If you can get over those 2 minor details definitely stay here.

Shared bathroom with one toilet, sink and shower for all rooms (4).
Initial welcome was unwelcoming and worrying, bad start to our trip.
Basic room

This B&B is close to the metro line, within a short walk to the Colosseum, but not in an especially attractive part of the city. The room includes the basics, the bathroom shared with the other 4(?) rooms. Breakfast is simple, but the packaged products are served with care. The host is very nice, very helpful, speaks many languages and cares for his guests. Good budget place.

I had a great stay at the Ariosto B&B! Very nice family run B&B. Helpful and clean. Only a 5 min walk to the Colosseum!