"streaming channels that should be free" is a little ambiguous. There's plenty of free content (usually ad supported), but there's also plenty of "premium" services that require a subscription. You're not going to get things like Netflix, Peacock, Paramount, or Hulu for free. You may want to add a PIN to your Roku account so you don't inadvertently subscribe to something that costs money.
How to create, change, or delete your PIN for your Roku account | Official Roku Support
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