Hi kazmi,
costs for housing are much less than in Addis. You can get a really nice villa for 2-4000 ETB monthly rent, if you have time to search you might even find houses for much less. Eating out is also cheaper than in Addis. What you have to get used to is that options are also less for dining out and grocery as well as leisure time activities. You can save a lot of money in Mekelle.