Toyota Repair: 1995 Corolla bauky starting, blue book value, wifes car

Question
We've just replaced the gas tank on my wifes car which costs more than the blue book value of this vehicle!

But this pesky problem is getting worse, and was present before the gas tank issues...

When inserting the key to  start the car, sometimes the car starts normally, immediately, and sometime it just clicks once...with all indicator lights lit.

Backing off the key and turning it again, sometimes starts the car (cranks and roars to life) and sometimes just clicks again (no crank over).

Today I've checked the battery cable leads and though corroded, they were cleaned and "lubed" (with a vasolene like terminal protector)but despite a good clean contact, still the problem.
Even checked the fluid level in each cell...they are all fine.

Answer
Could be a bad ignition switch.
When you said you checked the battery fluid level, did you check the specific gravity?  If the specific gravity is too low then the battery won't hold a charge.  You may have enough to start one time but not another.

Hope this helps

Vince

btw, 95 Corollas rock.  I had a DX wagon, stick shift