Currently the only reputable HD FPV system is the connex prosight HD, which is around $399 just for the camera/VTX
When you say:
Perhaps you are thinking about their HD goggles. These have an HD screen with HDMI input (if you connect it to a HD device), but in general most FPV systems are analogue so do not have a HD video signal. The highest resolution oyu can get is about 700TVL (irrespective of what camera you use) so its close to HD, but not true HD.
You might want to read our FPV gear guide to learn abit more about FPV stuff in general as there is quite alot to think about!