A device (not just Roku, but any device) will not have an IP address until it connects to a network. It could have a different IP address each time it connects.
You need a remote to connect it to a network. If you don't have a remote, the Roku 1 (model 2710) can be controlled with a cheap universal remote, as long as the universal remote packaging indicates it works with Roku. They're under $10 in the U.S., and can be found at many retailers, including Walmart, Best Buy, Target, CVS, and many other places.
DBDukes Roku Community Streaming Expert Note: I am not a Roku employee.
If this post solves your problem please help others find this answer and click "Accept as Solution."