Can't believe I'm the first east coaster to comment on this. Most of my camping is usually in NC, TN, KY, VA, and WV. Not only is there lots of places to legally camp, there are a lot of cheap small forest campground to stay at. A lot of these campground are under $10/night, 1/2 that if you have a discount pass. I've stayed in a number of forest service campgrounds with my discount at $2.50/night. Spent more money in fuel getting to the site than I saved but the isolation is worth it.
For the forest service campground and other government operated along with allowed disperse camping, check out ultimatecampgrounds.com. After I looked a lot on line confirming the small places I knew, I paid the %5 to download the poi list so I can use it in my offline mapping program and load it into my GPS so I can find a nearby place to crash when I'm ready to stop for the night.
In our area, there is dispersed camping off the blue ridge parkway just north or Mt Mitchel, a few more spots down near Brevard. Over in KY near Cumberland Gap is the Wilderness ORV area with some amazing views if you have 4wd and a smaller TC (see pic). Down in GA dispersed camping is allowed in Cherokee NF. VA gives you the George Washington NF and Monongahela NF.
Then there are the stores which don't mind you staying overnight if you ask first. Some of the more common ones are Walmart and Cracker Barrel. Just remember at this you aren't camping but are just spending the night so no awning, breaking out the grill, or relaxing in your chairs.
Regardless of where you spend the night, try to always leave it cleaner than you found it. This will help ensure it stays available for the next generation. I will usually stay a couple nights boondocking and then find a government facility with showers so I can get cleaned up, dump my tanks, refill my water if necessary and get rid of the trash I've made or picked up along the way.
