All the researched I have put into this question and questions like this seems to me comes down to this. Although all the home remedies that are listed may help to whiten your teeth only a dentist can get your teeth the whitest.
Here are some suggested home remedy that may help to whiten your teeth.
1)Brushing with Lemon Juice
2)Brushing with Baking Soda
3)Brushing with Hydrogen Peroxide
4)Brushing with Salt
5)Rubbing Strawberries on your teeth then Brushing off.
6) Orange Peels
7) Banana Peels
All though the above may help whiten your teeth they can do damage as well. They contain sugar and acids and are abrasive, all of which can damaged your enamel that helps protects your teeth
I can understand with all that been said that many people can not afford to go to the dentist to whiten their teeth. I would advise if you are going to try any home remedy to understand that you run the risk of doing more damage to your teeth in the along run.
Trying looking into some of the over counter products that are not so costly. Like tooth paste with whiting, mouth wash with whiting, gum with whiting. Maybe even just speak to your dentist and get advise on what he/she may advise for you. A good dentist will advise you on what you can use to help whiten your teeth. They may still tell you only they can do it the best (which would be true) but they still will tell you other ways if asked.
I hope this has helped you