The GIGABYTE GA-AB350M-Gaming 3 is the cheapest Ryzen board I can find at NewEgg and costs only $94.99 by comparsion.
Therefore, there's an obvious savings of $124. Although, you can easily spend $189.99 or more on a higher-end Ryzen board given NewEgg's offerings.
So while there is a discrepancy, it's not massive.