I bought mine about 12 years ago from Cavalier in St. Louis. I use it on a somewhat regular basis and have never had a single incident of trouble with it. I don't know about current prices but you could call them at 800-325-9023.
I actually bought mine through a used equipment dealer it is a Cavalier also. After I figured out how to use it right I've had no trouble with it. United's appears to be more or less the same. Call and get prices for both. I've got an older wand type that comes in handly for some things too, but I still like my Porta Wrap II.