The cost of living in Managua depends on your lifestyle. Generally, the cost of living in Managua is a lot cheaper than in Granada or Masaya because those cities are visited a lot by tourists, so the prices of ordinary things are higher than in Managua.
Living in Managua will cost you around US $1,000 per month and that includes electricity, water, rent and a maid. The rent for a 2-bedroom, 1-bathroom house with a little patio is about $300 - $400 per month, although, his will not be in the best or safest places in Managua, meaning this is not a gated area and it doesn't have security guards. This is in the working class area of Managua where people go to work to earn a living. There are no expats in this area, either.
For a $2,500 total budget for all expenses, you can rent a really nice 2-story house with 2-3 bedrooms, 2-3 bathrooms (1 in each bedroom) and 1 common bathroom, a couple of patios, a have a maid and a nice car. There is for a really nice community here, which is about 11 minutes away from Managua, called Las Colinas. It’s a nice place and even though it is not a gated community it is still really safe. People who live here are doctors, business owners in Managua, and some politicians.
In the nicest parts of Managua such as Santo Domingo (11 minutes away by car), fancy houses may cost up to $1,000 to $1,500 per month and you can live on a budget of $4,000 - $5,000 per month. You’ll have a really nice house with 4 bedrooms, 3 bathrooms, 2 living areas, a big garden and a pool with security cameras. You’ll have a really nice car, a couple of maids and send the kids to private schools. The people who live in Santo Domingo are ambassadors, politicians, and expats.