B&H Photo Video has Sony Action Camera Mounts on Sale from as low as $3.99. Shipping is free for for some of the Mounts and is $2.99 for others. The Mounts that have a shipping charge appear to be eligible for free shipping when purchased with an item that qualifies for free shipping.

• Sony Anti-Fog Insert for Action Cam (pictured)
  • $4.99 + $2.99 S/H = $7.98
    

No Longer Available:

• B&H
  • Sony Roll Bar Mount for Action Cam
    • $4.99 + free S/H = $4.99
  • Sony Surfboard Mount for Action Cam
    • $4.99 + free S/H = $4.99
  • Sony Clip Mount for Action Cam
    • $6.99 + free S/H = $6.99
  • Sony Action Cam Adhesive Mount Pack
    • $3.99 + $2.99 S/H = $6.98

Alternatively, Amazon has the Sony Roll Bar Mount for Action Cam for $4.99 but it is an "add-on" item (must spend $25 in order to purchase). Shipping is free w/ Prime or if you spend $35 or more. Thanks goldchocobo