A Pakistani Canadian here !! 
For the first year, just buy Plain Dark Shade jeans.. DO not worry u will be fine. 
If u are ok with buying Levis branded jeans from Pakistan (almost 3500 Rs approx), then u can easily afford Aeropostale and American Eagle brand jeans here for 30/40 $ , but as someone mentioned. U will end up paying 10$ for alterations.  
 
But i would recommend that do not go for Faded colors. Look for Dark, plain, single colors.  Plain simple Jeans is the way to go. Cant go wrong with that.
For T shirts i would suggest , Simple Polo shirts.  If u can find Lacoste , Polo ( #2)  shirts... U might have an edge 
Do bring a Suit with u as u might need it for presentations.  U can get it stitched cheaper then what u will find it here for.  
Dont go on buying the most thickest Jacket u can find. It will be  a waste. We use a concept here called Layering, to keep us warm. 
Its not one big jacket. Its actually the layer of clothes u wear that will keep u warm.   
Having said that, good quality sweater, ( Plain single color) might be helpful. Hoodies are very common here too.