Adobe stock comercial use

As free assets come under a standard license, you can't use such an asset for merchandize. 

 It depends on the design of your product. 

From the license terms page:

With a Standard license, you may not:

• Distribute the stand-alone file.
  
  
• Create merchandise, templates, or other products for resale or distribution where the primary value of the product is associated with the asset itself. For example, you can't use the asset to create a poster, t-shirt, or coffee mug that someone would buy specifically because of the asset printed on it.
  
  
• Transfer the license to more than one employer or client, unless separately licensed for each.

Read the license terms here:
License information and Terms of Use | Adobe Stock