If you have time to do the searching you can find 10-year old trucks with a full size hard sided camper attached and less than 100k on the odometer for as little as $16,000. You may have to drive to Nevada or Oregon or some other location that is 400 miles from your house but these deals exist.
The 10-year old truck has depreciated but is still a good RV vehicle and it comes with all the wiring and tie-downs and suspension and tire upgrades already in place. You have a fully functional rig.
Usually the owners have gotten too old or one has become an invalid or died and they seller wants to keep it simple and sell the truck and the camper together and is asking less than if they sold them separately. In addition 10 or more years old campers sell for less than $5,000 regardless of what they sold for new and odds are that new they sold for half what the same model sells for today.
The ones I saw outside of California and in Oregon and Washington usually had been stored in a barn and out of the weather which is a big plus over ones that sit out in the sun in California or Nevada or Arizona.