Adorama has the Rokinon 12mm f/2.0 NCS CS for EOS M as their Deal of the Day for $249 (Reg $319).
Rokinon EF-M 12mm f/2.0 Key Features
Fixed Focal Length: Focal Length: 12mm
Lens Type: Wide Angle Lens
Image Stabilization: Image Stabilization: No
Special Features: Aspherical
Filter Size: Focal Length: 67mm
Rokinon 12mm f/2.0 NCS CS for EOS M $249 (Reg $319)