$303 to replace a starter?

[DemoDisk]

My '93 Nissan Sentra wouldn't start so I left it with a neighborhood
garage which called me with an estimate of $303 for a new starter. Does
that seem like too much?

Replace starter (1-yr warranty) $169.73
Labor 118.00
Tax 15.28
======
303.01

Now here's the story: I called AAA Saturday evening because the car left
me stranded. It had never failed to start before. The AAA guy said the 6
yr old battery still had plenty of charge, but I might want a new one
anyway. The car required a push to start, and I went to Advance
Autoparts for a new battery.

'Clarissa' installed the new battery, and I turned the key. NOTHING!
Just then this big guy steps up and says "I've been watching, and I
think I can help." The hood is up, and he just reaches underneath the
air cleaner duct a second, takes his hand out and says, "Try it now."
The car starts beautifully! "Probably corrosion," he says.

Back home, though, the car wouldn't start. I tried getting under the air
duct, but there's hardly room for your hand, much less actual tools! So
I go to the place around the corner, which wants $300+ for a new
starter.

Question (besides the $300 one) : What did the guy in the parking lot at
Advance Auto DO to the car that helped it start?

Tnx,
Jm