Just thought I would share this. This was information given to my by the county. Might be of some thought.
(copy/pasted from my email)
My office does not issue a license for a lawn care service business, although if you are going door to door to advertise your proposed business, you might need a transient merchant license.
The link below to the Wisconsin Department of Revenue web site will have answers to your questions about starting a new business in Wisconsin.