My personal guess would be around $200 - $300 on public markets and up to $600 - $800 (or more) at the end-user. Your "right" buyer would be small and medium companies that manufacture custom circuit boards for different products, google for them, and this should be a starting point. Also 2900 avg. searches / month can bring value because they are niched. Adding a strong logo can increase the value with around 10%.