Hi,
sorry, from what I know there is NO free GOOD mesher. Of course it depends upon what you may consider "good" (possibility of local refinements, possibilitty to set number of divisions on edges / surfaces, possibility to control expansion ratio inside the surfs, etc...), and which kind of elem shapes it can handle (only tria or also quads, only 1st-order or also parabolic, also degenerate forms or not, only free mesh or also mapped / swept, etc...).
Regards