i'm using brush less motor-emax-gt2218-09-kv1100 , esc-avionic-40amp , servos(4 no's)-avionic-metal-gear-9g-servo-av90mg, can u suggest me what kind of lipo batteries should be used and what's the cost of it ?

You'll need minimum 3s 1000mAh. But it depends mostly on the type of plane you are planning to use it on.