No, it is not common for the components to cost that much but you are looking at high quality handmade gear. So in this realm, yes it is going to cost an arm and a leg. I generally use three batteries, on flying, one charging, and one cooling. With some planes that I fly a lot, I use 4. Get a good charger, the Triton is a nice reasonably prices charger that can easily handle these batteries or a Diamond Supersmart. There are also excellent European chargers out there if you want to spend the extra money.
Looks like one fantastic plane! Good luck with it!
Don