My company makes custom bobblehead dolls, and we currently hold the number one position for organic search under the terms bobbleheads, bobble heads, custom bobbleheads, custom bobble heads for all major search engines. Many other friends who own ecommerce companies have encouraged me to pay for sponsored links under these terms as well. I'm not sure if it works or not, and I want to test it somehow. Here are the complications:
1. Our customers do not buy immediately, they look around the website and then come back 3 or 4 months later and buy (its an occassion driven gift, so they wait until someone they know has a birthday). For that reason using the tracking code in google adwords to see if they converted seems not reliable.
2. I do not know if they would have clicked my website anyways if I did not have the adwords ad up, just using the organic search.
What I really need to know is how many additional customers I get by having the adwords terms up for these terms. Any good suggestions on how to do this? Keep in mind I do have three or four other competitors (they don't have as high organic search positioning though they are on the first page, and they do pay for adwords).