If you do a search on Amazon for 'PVR' you will get several under $40 results. I purchased an iView and HomeWorx brand a while back and they functioned the same. It takes a while to figure them out.
They come with no hard drive so you will have to add one to use the PVR function. They have only one tuner so you can only record one show at a time. The ones I have will display a very rudimentary program guide and it takes a long time to populate it. Once you change channels it has to populate the guide again.
I would suggest going with one that has the best user reviews. Hopefully they have improved the user interface and fixed some of the quirks.