You can use the free assets according to the licence for commercial purposes and non-commercial purposes, but in all cases, even for non-commercial purposes, you need to follow the licensing terms. There is no difference between free and for sale assets in this sense.
Look here for more information on licensing: https://community.adobe.com/t5/stock/links-for-licensing-terms/td-p/11366788 (Disclaimer: As always with licensing, this is my interpretation of the rules. I think they are correct and advice is based on reading and interpreting the licence terms and on fair use for both the buyer and the artist/stock company, but I cannot rule out that my interpretation is wrong. I'm not an Adobe employee).
ABAMBO | Hard- and Software Engineer | Photographer
Thanks for te explanation. I think Thais answers to the question related to standard licence of free assets: "3. License Terms and Specific Restrictions Applicable to Works 3.1. Standard License and Specific Restrictions for Works. The license described in this section 3.1 is referred to as a “Standard License”. (A) Standard License for Works. Under a Standard License, we grant you a non-exclusive, perpetual, worldwide, non-transferable (except pursuant to section 6 (Additional Rights)), non-sublicensable license to use, reproduce, archive, modify, and display the Work, in all media, for (1) advertising, marketing, promotional and decoration purposes; and (2) personal and non-commercial uses, up to 500,000 times as further described in section 3.1(B) (“Standard License Specific Restrictions”)."