In the past few years, we have covered plenty of awesome tesla coils here. They are not particularly expensive but not all of them are portable. This handled tesla coil gun is more easily maneuverable around objects you want to experiment on. It runs on battery and can light up gas discharge tubes, fluorescent bulbs, and shoot lighting at metals around you.
The above video gives you a better idea what you can do with it. It is always possible to disassemble the handle to remove and replace the battery.