I rent a very well-built and modern home in Arusha, very close to the tarmac road, for $600 USD per month. It is 3 bedrooms, 2 1/2 baths, sitting/living room, dining room and huge kitchen. It is unfurnished and I had to buy a small refrigerator and 2 burner cooktop that runs on gas. Unattached to the main house, it also has an askari hut, staff apartment, and a large room that can be used as an office, plus an enclosed garage. It is more money than I wanted to pay, and much larger than I need, but the closeness to the paved road makes it worth the money, and there is a fully stocked (expensive!) supermarket within close walking distance. I have looked at a ton of houses in Arusha and they were all too far from the paved road for someone without a car. I can be on a dala dala in minutes.
When I am there full time, it costs me about 100,000 tsh per month for electricity.
I use Vodacom for my phone and buy a Cheka bundle that runs me about 4,000 tsh per week. I use my phone from the USA, but phones can be purchased there for very little depending on the manufacturer and model.
Because I use a lot of internet, I supplement that with a SMILE internet bundle (5 GB of data) for 42,500 per 30 days.
Eating out depends on where you eat. I can get a plate of chipsi mayai for 2,000 tsh, or spend a lot more if I eat in more "western" establishments. Coffee in western coffee shops is about 4,000-5,000 per cup.
Dala dala fare is 400 tsh per ride.
I find because my Swahili is not good yet, and I am horrible at bargaining, that I get "ripped off" in prices a lot, so I let my Tanzanian friends do the negotiating and shopping for me when possible.
I pay someone (who lives on the compound), to do all the interior cleaning and exterior maintenance (yard work, etc), laundry, errands - cost is 200,000 per month. This person lives there 24/7 in the staff apartment and does everything for me, and will even cook for me if I ask. Speaks excellent English too!
Petrol is expensive, and traffic is horrible, so I sold my car. The most expensive taxi fare I have paid is 10,000 tsh and that is to go completely across town. Average taxi fare is about 5,000 or less.
I have a DSTV satelitte dish, which was cheap to buy and cheaper still to install, but the monthly service to get all the channels I wanted to watch was about 140,000 a month. I don't use it often (I also do not live there full time, still going back and forth to USA every 4 months).
My rental house was just hooked up to "city water" and so I am getting used to monthly water bills, so don't really have an idea of what the average monthly cost is yet, but it is pretty low, unless I am watering the gardens during the really dry seasons.
I have had to get medical care while in Arusha. The cost was unbelievably cheap, with NO insurance. I had an abdominal ultrasound for 100,000 tsh (about $75). Lab work one time when I had malaria cost me about 20,000 tsh.
The exchange rate for TZ shillings to USD ranges about 1650 - 1790 TSH per $1 USD.
Hope this helps someone.