I've heard more than once about folks hiring cheap help off the street, unlicensed contractors, from Craigslist, from the city mission etc, etc.
This help is invariably unlicensed and more importantly uninsured. If you are one to hire uninsured cheap help it would be wise to get substantial liability insurance coverage of your own. Here is just one scary story:
http://journalstar.com/articles/2009/06/13/news/local/doc4a32f6bd11fb5164103693.txt
A serious accident could happen on any jobsite and this owner's attempt to get by cheap will cost him dearly unless he is covered by a large liability policy.
Alway, alway, always ask for current insurance information even when hiring licensed contractors.