[SatvikBeri]

Slightly sleazier version: use a similar trick to get a discount when ordering new service, e.g. "I heard I could get a discount/fee waiver for plan X."

I don't consider this particularly sleazy because you can usually get the discount anyway if you haggle, but it saves a lot of time.

[PJones]

This works even better if you know what the deals are ahead of time, either from searching online or by knowing someone that works there.