Neutodol is good as it removes smells rather than masking them. I keep a gell ball in the centre armrest all the time.
I have heard that a small amount of vinegar left in the car overnight will remove cigarette smells.
I think the car will eventually be clear, but it could take some time. the carpets and seats would benefit from a proper wash-valet. Offer significantly less due to the extra cleaning required.
My first company car had been smoked in and it used to come out in hot weather.
hers - slk 320, his - dull diesel BMW fleet :/, Xtrail, Honda CBR 1100xx, Yamaha YZF600, Ribble Road
Also have a close look at the roof interior and around the window strutts. If it's been a heavy smoker you can get discoloration there that will be virtually impossible to remove.
Removing the smell of smoke from a car can be very difficult. If it's that ingrained smell then tbh - I would walk away. If it's a fairly fresh smell of smoke then you might be able to get rid of it. Depends how much the rest of the car is worth to you in terms of spec and value for money.