Yellow teeth

My teeth are slightly yellow in color and there are stains due to my smoking habits. I have started my smoking since my teenage. I tried quitting it but couldn't. Last night I went to a birthday party. While taking selfies I noticed my yellow teeth. I was lacking the confidence to smile and talk. I closed my mouth and posed for the selfies. One of my friends suggested teeth whitening procedure. So I’m considering teeth whitening procedure from a dental care clinic in Kingston but I’m not sure if my parents will support me. I just want to know the exact cost of this procedure. I have scheduled an appointment with the dentist in Kingston ( www.dawsondental.ca/our-locations/kingston-dentist/ ) on the coming week. Are there any risks associated with teeth whitening? Kindly share your suggestions. Thanks!!