Power/Electrical Issue 2000 Sunfire

For months my 2000 Sunfire had
been losing power while driving the
instrument panel (lights & gages),
headlights, and radio all stop
working sometimes hitting a bump
will cause this to happen sometimes
it just happens while driving down
the road. A trick I used to get
everything to start working again was
to turn my bright lights on and then
off, doing this would most often get
everything to work again. Well now
my car will not start it will turn over
and start for a second but then
quickly die. It is not the battery. It is
not the altenator. Anyone have any
idea what this could be? I thought
the ignition switch but I bought a
new one (black box that connects to
the back of where the key actually
goes) for $60 and that did nothing. I
priced the part where the actual key
goes its $250 I do not have $250 to
spend if it is not going to fix the
problem. Please help if you know
what this could be.