starting issue, loud click....then no power at all! please help

94 4runner, ran great all day, went on a 250mile road trip with multiple starts and stops, stopped into a casino for nice dinner, when I came back to fire it up it was in gear (which i forgot), I pressed the clutch override, when to start, it nudge forward, so backed off, put it into neutral, went to re-fire, all lights on dash were on, radio worked, but made a click noise and then, no power! I mean no lights, nothing, no door noise, got out messed with cables a lil, got power again, went to fire, click then no power again! So, when i would get no power, if i unscrewed the power to fuse box wire, removed from terminal waited a couple seconds and attached i would get power again, again all lights on, loud click, then boom no power at all, I tried jump starting it, but would get same thing, turn key, click noise, then no power even with jumper cables attached! So im a little confused, I was able to push start it and get it home, but wanted a little help if anyone else had this issue or could help, I was thinking starter relay just bc of the power cut off when turning the key. Battery tested fine. Any thoughts? Any help would be greatly appreciated, I plan on getting to work on it tomorrow.

 

I would change the battery anyways first.

Won't always start with jumpers if its completely shot. Tundra did the same thing when the factory battery took a dump.

Started her up moved the boat to the road. Turned her off while I loaded up and nothing not even when jumped.

 

Agree with @Dillusion, battery would be first suspect. Pull the battery, take it in and have it tested. If it is bad, the core is there for return.