This could be a great use for a voice AI chat bot connected to your phone line. Prompt it with something like,

“You’re on a phone call to [Widgets Inc] to get a price quote for a [box of premium widgets]. You’ll probably be put on hold to speak with the next available sales representative. Just wait until you get a person on the line. Then, ask for the price and immediately start negotiating for a better price. Use whatever strategy you want but never agree to whatever price they offer. Keep coming up with more ridiculous reasons that they should give you an even better price.”

Then dial the phone, turn it over to the chat bot, and wander off to go do more important things.