I use the Real Avid Master Armorer's tool kit. its pricey at $250 but drops down to $199 occassionally. Trust me after you build one, it won't be the last and it will be good investment in the long run.
My first build was with a regular hammer and cheap punch pin set from Harbor Freight.
Thanks for the tip. Does anyone have a recommendation on an all in one tool kit for building the gun? ( The adapter for the vice to hold the receiver, punch, and some of the small tools to deal with the springs/pins, etc.)