I've stayed here
Sejour Fujita in August through March for work. Their daily rate is pretty good and the staff is friendly. Also, as a weekly mansion the rooms are plenty big and you have a small kitchen. Unfortunately they speak no english. It is about 10 minutes south of Dobashi street car stop and 10 minutes west of the peace park on foot. However there are fewer restraunts, and I don't recomend the hotel restaurant, in the immediate area and it is only about 5-10 minutes closer than Hotel 28 is to a street car stop or the Peace park.
In April I stayed here
Comfort Hotel Hiroshima. It is acrosss the street from the Chuden-mae street car stop and 5 minutes from the Peace park. However the rooms are tiny about 8' x 7' around the bed. I think everybody I encountered at the front desk spoke enough English that I didn't have to attempt my pitiful Japanese. The location is really the best part of this place there are a variety of restaurants within 5 minutes walking distance including Nobu Creative Sushi which is across the street and is run buy an English speaking Japanese man that lived in L.A. for many years so you can get really good traditional Japanese sushi along with Americanized versions like California rolls.
Comfort Hotel Hiroshima Otemachi is about a block south on Rijo-dori but I've never stayed there.
Crowne Plaza ANA Hiroshima is just across Peace Boulevard.
In July I stayed at
Hotel Granvia Hiroshima. It is right at your limit of $100 for a single room. It is attatched to Hiroshima station which makes it convenient for restaurants and also taking the street car once you figure out how to get from one side of the station to the other. The
Rhiga Royal is another hotel in this class but it is located central to Hiroshima Castle and the Peace Park. It is about 5 minutes north of Kamiyacho-nishi street car stop on Rijo-dori.