You will never get rid of the smell. My house had a thin microscopic layer of cigarette smoke 'residue' over every square inch of it when i bought it. I junked every piece of fabric inside the house when i moved then washed and cleaned every single hard surface , painted everything and replaced all of the yellow elctrical fittings (light switches, plug sockets, light fittings , etc ) for new white ones , despite having lived here for 6 years, and despite the fact that to my knowledge nobody has ever smoked in my house whilst i've owned it, i still get the odd whiff of cigarette smell if i look into some nook or cranny that hasn't been disturbed for a while.
Basically there are plenty of s/h cars out there , you don't need to buy this one regardless of its price and you'll never be totally happy with it....