I have not launched my adword campaign yet. I am still researching keywords. But the traffic estimator seems to be giving erratic results which is why I cannot make up my mind regarding most keyword phrases. As for example, I have chosen United States and entered [bargain new cars] into traffic estimator. CPC, Estimated clicks/Day, impressions come up zero. But when I enter "bargain new cars" into google, it returns a number of PPC adds. Note also that although I am not in the US, I have a firefox addon that helps me view the results if my location were in the US. Why this inconsistency? Further, the previous interface of Traffic Estimator, and the present interface give different values. Which one is more reliable? I have to submit a marketing plan ASAP. I would really appreciate it if you had any suggestions or explanations. Thanks

Just because Firefox thinks you are in the US it doesn't mean Google does. Your IP doesn't change.

Maybe the add on is tor? although I should imagine google knows all the tor servers.

First of all, i too was in a fuss. But you can get the keywords, phrases by going on specific search engine and type the related keywords, phrases. You will get the most used, popular, searched keywords, phrases there. you can add them in your adwords account. After adding in adwords account, you will get minimum bid, it will tell you how much the minimum bid is for that specific keyword.