If you want to buy a 4g tab in budget then iball slide brisk 4g2 is a good option for you it has 3gb ram so it never hang when you uses high graffic applications on it .
Its network quality is very good as compare to other low budget tabs it gives you best network surfring + it has wifi option and voice calling so that you can always be connected .
Iball has good costumer service but it takes some time to repare your tab but they do it nicely and always answer your call.
Iball slide brisk 4g2 comes for ₹8200 that is perfect for this tab , this tab really gives you value for money .with 7 inch hd screen and 5 mp real camera , a good 1.0gh fast procesor , 6.0 latest android version marshmallow