I think the person meant the truck costs $200,000 by itself and the conversion was an additional $349,000, for a total of $549,000 and he is selling it for $369,000.
I do not know if $200,000 new for the truck was a reasonable price....it is definitely a big ass truck. It can probably tow 60,000 pounds or something ridiculous.
$349,000 for the conversion sounds like too much but it does seem to have a lot of custom fiberglass or something. This is not a vehicle you are going to live in down by the river but rather something you are going to haul your $500,000 race cars to the track or show.
As a comparison, we have spent about $30,000 on our camper (rough estimate although I have receipts to total) but we did EVERYTHING ourselves including painting it. Probably will be another $7,000 for the garage pod when all is said and done (automotive paint and truck bed liner is not cheap). We bought a used truck, but a brand new Isuzu NRR with 20 foot flatbed is about $60,000.
We probably have about 3000 man hours into our build. If you were to hire this out at $20 per hour, that is $60,000 labor.
Still, $549,000 seems very expensive.