Just as the other comment said, "that's only the conversion kit". I didn't want to wax poetic about the various input costs to a project like that but let's just say I and several of my friends know how much they can cost on both the upper and lower ends.

If you DIY hack it together with junkyard motor and spend nothing on anything you can get away with a self-made conversion for ~5k. If you're buying your parts from a kit like these links and using new crate motors then you will never get under 12k. Not to mention the cost differences of you doing the work vs a mechanic. The cheapest turn-key mechanic-done conversion with a new motor won't be under 15k and will likely push in the 20k+ range.