This seems to be a good price for this unit. The P400A D-RGB linked below and this power supply should go well together.
SKU # AC36087 | Model # ERF850EWT
Enermax REVOLUTION D.F Series 850W 80+ Gold Fully Modular Power Supply - Total Power: 850W - Input Voltage: 100 ~ 240V - Input Current: 10A - Input Frequency: 47 ~ 63 Hz - OCP, OVP, UVP, SCP, OPP, OTP Protection - Dimensions: 160 x 150 x 86 - ERF850EWT - 5 Years Limited Warranty
Manufacturer Warranty: 5 Years Limited Warranty
Also found this case deal for a P400A D-RGB for $99:
Black
White
SKU # AC26452 | Model # PH-EC400ATG_DWT
Phanteks Eclipse P400A D-RGB Tempered Glass Mid-Tower E-ATX Case - White - 7 Expansion Slots - Drive Bay Support: 2x 3.5" & 2x 2.5" Internal - Fan Support: 3x 120mm or 2x 140mm Front, 2x120/140mm Top & 1x 120mm Rear Fan - Fan(s) Included: 3x 120mm Digital-RGB Case Fans - Supports Up to E-ATX Motherboards (Up to 272mm Wide with HDD) - I/O: 2x USB 3.0, Audio, D-RGB Button - Powered Coated Steel Chassis - Tempered Glass Side Panel - PH-EC400ATG_DWT - 5 Years Limited Warranty
Manufacturer Warranty: 5 Years Limited Warranty
Manufacturer Contact Info: http://www.phanteks.com/,
amazing deal