1995 Delta 88 Wont kick over

I will make this as brief as I can....My delta 88 starts when it wants too..lol. Example...I started the car with no problem and let it warm up for about 15 minutes (it was 20 degrees out) then took it for a short 3 minute ride and shut the car off. Then about 2 hours later I went out to start it again it just wouldn't crank over..it sounds like it wants to but it does not. I waited about 3 more hours and it still would not start, so I called a tow truck to take it to a Olds dealership and when the tech. went to get the car it started right up. (See I told you it has a mind of its own.)..LOL. I am going nuts about this...this has happened twice now. The first time I had it towed to a local garage and they too said, it started right up. But they replaced the spark plugs and clean the battery and charged it and it was fine for about 3 more starts...then it proceeded to start then not start again. I talk to the the tech at Olds and he said it might be a fuel pump but is not sure. He is going to run it for a while then shut it off and then try to start it again...Watch I bet it starts right up for him..LOL ( I am begining to think I am crazy). Do any of you guys have any suggestion on what it might be? I really appreicate your input. Also are fuel pump replacement prices about $400.00 if a dealership does it?