I believe you as even I have received such rich clicks few times. One was $7+. Congrats!! These days it is rarely seen however.
Seems to me that some one have buy through your link and google transfer the comission to you. This can be of now or may be of earlier days. Best of luck.
That just says you need to work hard on that car site you have.. Churn out 3-4 articles a day. Get some good links.. keep working. If you got a 5 dollar click once, it is possible to get more, no? I guess it must have been a Car Insurance ad.