Newegg has the following 3 item combo for $309.98 after combo and MIR:
Intel Core i5-7600K Kaby Lake Quad-Core 3.8 GHz LGA 1151 91W BX80677I57600K Desktop Processor [$239.99],
MSI Z270 MPOWER GAMING TITANIUM LGA 1151 Intel Z270 HDMI SATA 6Gb/s USB 3.1 ATX Intel Motherboard [$239.99],
and MSI DS502 USB Connector Circumaural Gaming Headset [$44.57]
headset adds in checkout, for $479.98 - $130 Combo Discount - $40 MIR = $309.98 +2.99 S&H
$524.55 total retail value.
Intel Core i5-7600K Kaby Lake Quad-Core 3.8 GHz LGA 1151 91W BX80677I57600K Desktop Processor [$239.99],
MSI Z270 MPOWER GAMING TITANIUM LGA 1151 Intel Z270 HDMI SATA 6Gb/s USB 3.1 ATX Intel Motherboard [$239.99],
and MSI DS502 USB Connector Circumaural Gaming Headset [$44.57]
headset adds in checkout, for $479.98 - $130 Combo Discount - $40 MIR = $309.98 +2.99 S&H
$524.55 total retail value.