In most cases, the answer is “yes”, it’s cheaper to boondock than to stay in RV parks.
But it depends on what RV park you’re comparing it to.
Some RV parks located away from urban areas will offer monthly rates so low that you can save more money on their grounds than by boondocking. It’s common for some of these parks to offer monthly rates as low as $150.00 a month, and still offer you electrical, water, and sewage hookups. However, these parks will charge you separately for the electricity. But, electrical costs generally work out to $75.00 to $125.00 a month on average usage.
However, these RV parks tend to be unkempt, dirty, or populated with undesirable folks.
During the hotter months of the year, boondockers may have to run generators to power their air conditioning units (very few have enough solar power to run cooling off of battery), and over the course of a month, the fuel needed to run these generators, along with propane and dumping costs, could make boondocking more expensive than these cheaper RV Parks. There’s also the cost of maintaining a generator, such as oil changes, air filter changes, spark plug changes, but rarely exceeds $50.00 a month.
Being able to move to cooler geography around the country can put boondockers in a position of not having to rely on air conditioning so much.
Moreover, most boondockers will have to move their RVs at least once or twice a month to new locations due to maximum stay limitations, thus the cost of gasoline or diesel to drive their rigs adds to the overall boondocking costs.
Outfitting an RV with adequate equipment and components necessary for long term boondocking will run into the thousands of dollars.