Yes, the Startup Disk Creator that comes pre-installed in ubuntu (
usb-creator-gtk) allows a persistent option while creating a live-usb install.
Increase the space to whatever you find reasonable. Persistence gives you the freedom to save changes, in the form of settings or files etc, during the live session and the changes are available the next time you boot via the usb drive.
usb-creator limits your live persistent partition size to 4gb, though. To bypass that limit, you would need to edit the partition, and re-size it using a partition editor (such as
See Live Usb Persistent on the ubuntu wiki for more information.