I can't for the life of me remember the web site, but there's a site out there that sells really inexpensive (yet still good quality) bottle heaters, remote openers, exc.... I'll search around and try and find it.
It's Dyno Tune brand. Here's the link. They're 149.99 (towards the bottom of the page). That's a heck of a lot cheaper then on the NX web site. They're got some pretty cool nitrous stuff on that site.