Fallout 4 how to get 3200 caps from Machete Mike, Far Harbor DLC

When helping out The Mariner, she needs Power Tools. Once retrieved, Machete Mike will ask to buy them. Use Speech to up your price in Caps, rob him after....**KILLING MACHETE MIKE LOCKS YOU OUT OF THE LAST 2 MARINER FETCH QUESTS** Then go get Reward from Mariner. That&a lotta Caps!!! Fallout 4