Car camping
Car camping is exactly what it sounds like. You pack whatever you think you'll need to camp for a weekend or a few days into your car, drive to a campsite, set up camp and enjoy the great outdoors.
From a price perspective, nothing beats it, because your only costs are:
any gear you don't have
a campsite
entrance fees to county, state, or federal parks
gas to drive your vehicle to, from and around your location.
It is the most affordable way to experience state and national parks of the United States with a minimal investment in gear.
Above: Car camping: drive to your campsite and unload.
Above: Sharing gear, experience and good times with friends.
And it can be even more affordable if you travel with a companion or other couples. Besides being a lot of fun, others will often have camping equipment, knowledge and experience to share with the group.
This is especially helpful if you are new to car camping and are not sure it's for you.
If this is your first time camping: Consider renting gear from a sporting goods retailer, like REI or borrowing it from a friend.
Members of the military can rent equipment from MWR (Morale, Welfare and Recreation) on base. Rental equipment is usually rugged enough to survive being rented and better quality that you might be able to afford if you were to try and buy everything you needed.