1997 Ford Elite Ignition problem

I stopped at a stop sign down the block a few days ago and when I dropped into first and started to accelerate the engine cut out. It felt as if I'd not given it enough gas, so I attempted to restart. When I did everything had gone dark. No lights, no instrument panel, no radio. Someone tried to give me a jumpstart, but no response. We then tried a push start, and again, nothing. I took both the battery and the starter to get tested. Both came back good. I reinstalled them and when I did the panel lit up, but when I tried to start the engine, everything went dead again. I'm at a loss as to what the diagnosis could be and I'm really financially strapped. I can't afford a big repair bill right now. I was hoping to get it done myself if I could. Obviously, I'll take it in if its too big for me to handle myself, but I've replaced a starter and alternator myself, do I tried to eliminate those possibilities. Thank you very much for any help you can offer.