1999 Toyota Camry Transmission pan gasket change-cost?

Transmission problem
1999 Toyota Camry 4 cyl Automatic 101000 miles
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Hello all,
I recently took my 1999 camry to the local Toyota dealership to check the A/C, and they said that the trasmission pan was leaking and that the gasket needed replacement. Does anyone know how much this would cost? They did give me a quote, but I am choosing not to mention the number here, so that I don't bias anyone who may respond

I am a little wary, because I never see any patches on the ground even after I have parked overnight at the same spot.

Thanks so much for your help.
Mathew