All the free ones seem to have some kind of limitations or provide results which are somewhat unsatisfactory.
That's just my personal opinion. Even some of the fancy ones that cost money, well, suck. But then i guess it depends on what you want to do and how meticulous you are. A few suggestions have been posted in here.
If you have CAD just import the picture and draw over it.
"Magic wands" cost money.
FWIW,
Rich