Locally bhi mil jata hai,almost har cigarette shop se,par wo apko at least 1000 rs ka milay ga yahan se.
Don't know about ke Karachi main kahan se mile ga,but i'm sure it'll be lot more easier to find it in Karachi than Islamabad
.12mg Nicotine level is good for starting,then you'll go as high as to .36mg,according to your needs