As long as your Roku isn't one of the Stick models, you can easily pick up an inexpensive universal IR remote that lists Roku as a supported device. If you have a Stick, you're out of luck there, as it doesn't support IR remotes at all.
You can usually find IR remotes for under $10 at almost any store that offers electronic devices. Places like Best Buy might be a bit more expensive, but they're usually easier to find.
Dan
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