(the suit ITSELF should cost $100 or less. The actuators may add to the cost)
Ok, building a steel frame with hinges to be a suit, i get that. That could be done under $100 if you have a cheap source of metal.
But the actuators, the electronics, the drivers, the force sensors, that's upwards of $10,000 US (closer to $100,000 or more), alone.
And the metal your using isn't what I'd call load bearing. It's not being built up in a structural manner, it looks like you're using stuff barely thicker than strapping. Case and point: you bent it and built into shape with no welding, no heavy bending equipment. It's not pipes or i-beams, it's jus straps (from what I'm seeing)
Like, a steel and aluminum costume would be amazing. But power armor... well... simply put: how are you going to power it? Arc reactors don't exist, and there's basically no equally compact power source in terms of weight to power output ratio other than a gas motor.
I hope you end up with an awesome costume, but you should be planning for that, not armor that the military hasn't managed to create while actually actively pitching millions of dollars at the project.
(Reason I can state this: Bachelor of mechanical engineering here, currently finishing a masters in materials science and engineering. Also the agreement of everyone else on this site.)