I have 132,000 miles on my 2006, 530i. Should the transmission be serviced?

Has the transmission ever been serviced? Have you had the vehicle since new? Do you have an automatic or manual transmission? Per the "normal maintenance" schedule for your vehicle, the transmission fluid and filter should be replaced at 100,000 miles.

Highly recommend getting another auto repair facility's evaluation & estimates. I know BMW is an expensive vehicle to maintain but I think the price you were quoted is a bit much.