LAN & Online 3D Shooter

I want to build a highly addictive 3-D shooter that looks and feels realistic, works both offline and online, and lets players jump into competitive matches over the same Wi-Fi network with zero configuration... (Budget: $25 - $50 USD, Jobs: 3D Game Art, 3D Modelling, C Programming, C# Programming, C++ Programming, Game Development, Unity, Unity 3D)