Nifty, but $800?

I found this interesting, but kind of expensive, product here:
I was wondering if someone already built something similar based on arduino.

Hmmm…given that the NAV module itself is $500 (!) then they’re basically charging $300 for the board and the software.

Worth it? Dunno…I think you’d still need a PCB for hooking it up to an Arduino, but it wouldn’t take $300, just some time.

Would this be a cheaper alternative: