How much is this used system worth ? Need reply asap

$2350 is a new build price mate - meaning you could do it yourself for the same money (- os)

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-6600K 3.5GHz Quad-Core Processor ($227.99 @ SuperBiiz)
CPU Cooler: Corsair H115i 104.7 CFM Liquid CPU Cooler ($114.99 @ Newegg)
Motherboard: Asus Z170-A ATX LGA1151 Motherboard ($149.39 @ B&H)
Memory: Corsair Vengeance LPX 16GB (4 x 4GB) DDR4-2400 Memory ($77.37 @ Amazon)
Storage: Kingston HyperX Fury 240GB 2.5" Solid State Drive ($78.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($45.71 @ OutletPC)
Video Card: Gigabyte GeForce GTX 1080 8GB G1 Gaming Video Card ($624.99 @ Amazon)
Case: Corsair 780T ATX Full Tower Case ($149.99 @ Newegg)
Power Supply: EVGA SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($87.98 @ Newegg)
Monitor: Asus ROG SWIFT PG278Q 27.0" 144Hz Monitor ($659.99 @ SuperBiiz)
Keyboard: Corsair K70 LUX RGB Wired Gaming Keyboard ($159.99 @ Best Buy)
Total: $2377.38
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-09-25 14:12 EDT-0400