@Redlin: For your soul, I'd say a truckload of gold. Would you like me to shatter your soul and claim a part of it as payment?
@Hman: I can do better. I can sell you a hip replacement with a concealed weapon. Said weapon shoots micro pitchforks.
I can also upgrade the micro pitchforks with one that have an electric charge that'll shock any witch (or anybody else for that matter) dead in their tracks.
@Neo: Can I interest you in a super duper vulcanised rubber band, forged in the depths of Mount Doom, to replace the one on your harpoon?
Or is it the air-compressed variety? For that, I have a compressed canister of lost souls that's launch your pitchforks at super sonic speeds. Witches will not even hear the pitchforks coming until they pass right through them, before being blow to pieces by the sonic boom.