recomdend any head which is easy

[Alwin Alcott]

i am totally mesh for years, because i wánt it .. but it's absolutely not  neéded.

One of my alts is a girl ( for pose adjusting reasons) and only wears a slink body with no mesh head. Even after all the years i think.. well.. a mens eye.... she looks good enough to go out on saturday night

[Lewis Luminos]

If you need an easy head and it absolutely needs to be free, the best head is the system head. Provided that your body (if you have one) is set up for Bakes on Mesh, otherwise your skin won't match at the neck. Even with Bakes on Mesh, there will still be a slight seam, such as in @Alwin Alcott's pic above. Seams can't be avoided without being mesh on both head & body or neither. 

So if you want easy AND free AND no neck seam, you're better off remaining entirely non-mesh and sticking with a system avatar, until such time as you're willing to spend money.