If you are anything like my father, you've already moseyed down to the junkyard, picked up an old streetlight and attached a basketball backboard and basketball hoop to it. As long as you're not afraid of pouring a little cement and don't mind hacking through a thick tube of galvanized steel, this is not a bad way to save some money. Most people aren't like my father, however.
More reasonable options
Your best bet is probably a portable basketball hoop that is weighted down with many gallons of water or sand. While you never expect to move a basketball hoop as often as your average coffee table, you may find the side you thought you liked gets some mean sun late in the evening. At any rate, portables give you options.
A rather permanent choice
If you know, however, exactly where the hoop is going to be placed, go with the stationary, inground basketball hoop. A well-placed, well-maintained basketball hoop is useful for all sorts of things and likely adds value to your home. As soon as you have it set firmly in cement, you've got a nice post for half of a volleyball or badminton set-up. If you're creative, you could probably make tetherball work, too.
Something to consider
A third variety, the wall-mount basketball hoop, is a fine choice, but should be considered a compromise. A lot of interesting play happens just behind the basketball hoop, and is rendered impossible if your basketball hoop doesn't hang over the court by about 3 feet. But it's better than nothing and should be considered when parking arrangements or just the general layout of the cement doesn't allow for a basketball pole to be inserted.