Other mounts are the same price. If you do choose this route, I'd recommend going for a Canon or Nikon mount version. You'll need an adapter regardless and if you ever need to sell the lens, having a popular (i.e. not 4/3) mount will be a big advantage.
The m43 7.5mm f/3.5 lens from Rokinon is available, not on sale, from the same vendor for $270.