Land & Ground based robots
Land based robots are the easiest to design and most popular among the robotic community. As a beginner, one should always prefer building a land based robot due to their simplicity, cost factor and their exposure to greater knowledge. Of course there are complex land based robots, but simpler is better for a beginner.
There are different types of land based robots (well, I somewhat feel like the term land based robots sounds "not so good" Since I did not find a better term, will continue using it). The most common land based robots built are: