Why the range is so wide
Two products can both be called a red light bed and be built nothing alike. One may be a folding mat with a few hundred low-output LEDs; another may be a rigid clinical canopy with several thousand binned diodes, published irradiance at the body plane, active airflow, and a commercial warranty. The light dose you actually receive per session can differ by an order of magnitude.
Because of that, a price on its own tells you very little. The useful question isn't "how much is a bed" but "how much bed do I need for what I'm trying to do" — and that's a short conversation, not a spec sheet.