If I purchase a second Roku device for a different room in my house is there additional charges?

There are no charges in the first place, so it's not clear what you're asking.  Roku is free, but "premium" services require subscriptions.

Hi, Sherrybaby1 

Thanks for posting, and welcome to the Roku Community.

I appreciate your inquiry about adding another Roku device, and I'm here to assist.

Roku does not charge when you add a Roku device to your Roku account or create a new one.

Additionally, if you have an active subscription, you will not be charged additional fees when you purchase a new Roku device if you activate it using the same Roku account with an active subscription.

I hope this information helps, and keep us posted if you have further clarifications.

Thanks,
The Roku Community Team.