the natural assumption for freebies here is that:

1. they're free for non-commercial use
2. give the freebie creator a percentage of sales for any commercial use

AFAIAC there's no need for the freestuff providers to hafta spell that out.
it's too obvious for words IMVHO.  like if ya leave yer keys in yer morris mini,
it ain't necessary to put a sign on the window saying "please don't steal my car".