a reasonable set up will be $80,000-200,000
very high risk of vehicle damage which may not be coverable by insurance
components fail rapidly or at least wear out perhaps 4x faster than normal if you go through mud or water crossings
lots of gear needed, in particular, recovery gear, fridges, spare parts, batteries, gas bottles, 50-100L water, cooking gear, etc
corrugated roads add to the damage risk to gear and vehicle
fuel consumption costs are higher
most keen 4WDers will make substantial after-market vehicle modifications
many will add a trailer or van