1997 Ford explorer brakes?

I have absolutely no brakes on my explorer when you push the brake pedal down it goes all the way to the floor. I have had 3 people look at it and everyone tells me something different. We thought air was in the brake lines so we tried to bleed the brakes that did no good. Thought the Calipers were bad changed them still no good. Two people looked at master cylinder and said it was OK another said it wasn't I'm at a loss. I have done spent around $250 trying to fix it in the past 2 weeks and am about to pull my hair out. I am a single mom with 2 kids and I need it so I can get back and forth to work daily. Does anyone have any suggestions? I cant afford to take it to a mechanic so any help on here would be greatly appreciated