If you dont want to spend 1000 $ or more then you cannot use Unigine, Lawmaker or Unity3d (all 3 are superb alternatives).

You have to choose between free alternatives like Ogre and Irrlicht. Or you can start with engines that cost only a few hundret dollars like Torque Shader Engine (TGEA), C4-Engine or S2-Engine.

If you dont have much money then you will have problems to buy expensive modeller tools like 3ds max. So S2-engine is not a good choice for a free project except you have warez-modellers in your team. But I dont recommend to rely on warez at all.

TGEA supports lots of modellers and C4 can handle Collada files. Both have shader support, great shadows and lighting and fast renderer.

If you just want to make a shooter then you can even start with scripting only but if you want to make something different then you need a C++ coder in both cases.