How many vehicles can a private seller sell in one year in arizona?

I did some research and found out that I can sell 3 cars a year legally in arizona without having to get a license for selling cars. So my question is really what is under these terms. Is a motorcycle sale considered one of the 3 sales a year? How about any atvs or fourwheelers? Please add a link to where you found info. I appreciate the input im advance because I don't know how to comment on my own questions.