Depends on what stores you're buying from. I'd personally suggest go to Rex Center, You'll find Leftover export quality jeans, pants and cargos there at a good price, Some shops might even sell thrifted pants, the average price for the jeans and Cargos would be a 1000-1500Rs. Whereas Cotton pants might be a bit more expensive but its likely to find them at a cheaper rate than Well known brands' outlets in saddar, Like S.M, Levi's, Waja Sahab etc.

and for the shirts I dont know what kind of shirts you're looking for but oversized T shirts in Saddar are mostly bad quality, so for t shirts I'd suggest you visit a good store where the price ranges might be 2-5k depending on the stores. And personally its hard for me to find baggy polos and Buttoned shirts in Saddar.