Many cities have both temp services, and day labor places. These can be a great resource for temporary jobs while traveling. If you're not picky, there are usually plenty of jobs available that most people don't want.
With experience and a little creativity, there is a lot of money to be made flipping finds at flea markets, yard sales, craigslist, and thrift stores.
I also know several people who will drive up to any construction site and ask for a days work, and usually get a job cleaning up debris etc.
Cleaning windows at restaurants and small businesses supports several people I know too, they say there is an unlimited supply anywhere they travel.
Another couple I know clean restrooms at bars, restaurants, gas stations, and small businesses for $5.00 At restaurants they sometimes barter for meals. They wintered in Tucson a couple years back, and said they were making upwards of $100 per day for a couple hours of work, and that they supported themselves during their travels doing the same thing.
One full timer I know who travels with the weather, says that where there's good weather there's carnivals, and where there's carnivals, there's work.
Another writes: "There's always sign waving jobs, work a week a month and enjoy life."
Still another does face painting at flea markets & swap meets.
There's no shortage of ways to make money on the road, you just need to think outside the box a little bit sometimes. Flea markets are a treasure trove of buyers, and I know people who sell everything from cartoon stickers to identity theft kits at them and make a decent living while traveling and enjoying themselves.
Someone once wrote "If you do a job you love, you'll never have to work a day in your life.". Find your niche and go for it.
