Search the site for "without subscription" and you should turn up a few threads covering your situation and which box would be best for what you have in mind. (I'm pretty sure the Premiere completely disables itself without a sub now, the older ones may not).
You may need to subscribe whatever you get for one month to get it set up, but they've done away with the 1 year commitment period, so you can pay $12.95 one time and then cancel.
