The tariffs were mandated into law by the US Federal Government, with the first 10% on October 1st 2018. A 15% additional tariff will be added by the US government on January 1st of 2019.
Just to be clear it isn’t the companies doing this, but the US Federal government.
It depends on whether the vendors eat some of the cost or they forward on the cost to consumers.
Products from Amazon.com
Price: $268.98Was: $319.99
Price: $389.99Was: $489.99
Price: Check on Amazon