I only wish they were more straightforward with the pricing, it's literally included with the parts as far as I can tell (don't know if they show more charges at checkout). So the extra $200 with the 690 vs the extra $40 with the 670 is confounding (well, ripping off is a more accurate). But I guess showing you bold text about things you're getting for "free" is more a priority.
Building it yourself isn't too hard actually, it's like a giant puzzle with instructions. There's youtube vids showing you how to do it too. The only other requirement is time to do it (and the right parts, but internet people can help with that).
https://www.youtube.com/watch?v=lPIXAtNGGCw