Hello Mahesh.mrj,
Below is a brief reply to you question, in Ugandan shilling currency (UGX).
1. 1 Bedroom studio apartment with facilities (In Entebbe as you will be working there prices range from UGX 400,000 to 1,000,000 per month depending of quality and security)
2. Water cost per bottle (Depends on size & brand but 500ml bottle of water range from UGX 500 to 1000
3. Food cost per day if from a restaurant 3 times a day (Hotels in Entebbe have great food to start you off so you can adapt but various restaurant and Lido beach close to the UN base has some great food. e.g Full English breakfast cost UGX 5,000 ; Full lunch depending on what you eat UGX 7,000 and Buffets are also available for about UGX 10,000.)
4. Petrol price per litre (UGX 3,400 petrol)
5. Clothes (Suggest you bring your own but lots of shopping malls in the capital city Kampala to buy at very affordable prices)
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6. electricity charges (depends of what you use but relatively cheap if you use Calor Gas for things like cooking at home, you get to save a bit more).
7. Bus fares (from UGX 500 - 1,000 for local trips but goes up if your going on longer journeys but still the cheapest transport in Uganda.
Hope this helps.
PS
Do let me know if you would like to view some fully furnished properties for rent in Entebbe or Kampala to meet your needs.