I play around with a lot of Linux distributions and while I typically just virtualize them using an app like Oracle VirtualBox or VMware, sometimes it's nice to be able to test them on bare metal. A nice, pain-free way to do that is with Pendrive Linux's Universal USB Installer.
The Universal USB Installer is easy to use. Simply choose a Live Linux Distribution, the ISO file, your Flash Drive and, Click Install. Other features include; Persistence (if available), and the ability to format the flash drive (recommended) to ensure a clean install. Upon completion, you should have a ready to run bootable USB Flash Drive with your select Linux version installed.
Universal Installer can create persistent storage on your flash drive. That means you'll actually have some permanent space to save things like files and preferences -- instead of just having a flash drive clone of your disc image.
Universal Installer supports a large number of linux distrobutions such as Ubuntu family, Mint,Puppy linux etc..