Driver PCB doesn't have slits, you'll have to cut it yourself. I partially sawed them along, then broke carefully in a vice.
1 big board, i.e., 2x2=4 small boards: $5, 2 big boards: $7.
1 small board: $3, 2 small boards: $4.
World-wide flat shipping: $7. Shipments will be from Moscow, Russia.
Priced so that it will be a little cheaper to buy from me than to order yourself. You'll unlikely need more than 8 small boards, it'll cost you 7+7=$14, while if ordering yourself you'll get 40 small boards, for 10+5=$15. But you are free to order yourself, and sell them as you wish, I don't mind.
My email: abvgdee(at)mail(period)ru
Linear regulators I bought from fasttech.com.
Turnigy silicone 18AWG wires, and XT60 connectors - beyond any praise, very well designed and manufactured - from hobbyking.com