Q. Is their any price difference in dual tone and single tone - Creta?

Yes there is huge difference in price. I would not suggest you to opt for dual tone if you go for it than have to spend 3- 3.5lakhs only for dual tone but you will some extra feature also (Like chrome work, leather staring rare parcel etc.) which you can go for aftermarket with in the cost of 50k.

Yes

Yes, the dual tone has a greater price