Suggest me bike with best mileage and performance for Rs. 40000 to 50000

[amarya]

Hi I need a bike which has best mileage in has best performance in the price range of Rs.40000 to Rs. 50000. I am college going student but have budget not more thank 50K , please suggest me bike which is not heavy on my pocket because of fuel. I will be using it a lot for communting and if it has bad mileage then I don't want all my money eaten by it. I also want some good performance. So please suggest me balanced bike.