To get a grip on orbital elements, I'd like to play with a ready interactive visualization like in Universe Sandbox. E.g. drag the inclination slider and see immediately what happens to the satellite orbit. Are there any free tools capable of doing this? I wasn't able to find such a function in Celestia or Stellarium so far.
If all you need is a quick and free tool to visualize orbits around earth, websites such as the following might be enough:
First, the very simple orbitalmechanics.info, where you can just ignore the "add launch" option:
And then, the more artsy Harmony-of-the-Spheres, which can also visualize some other systems.
Maybe that already helps.