So maybe you've been in this situation… You want to practice in your apartment or home, but its mainly carpet. Also, getting wooden floor panels costs too much. Well, there is a simple solution (thanks to Alex for this tip). Go to Staples or Office Max and get a couple of those plastic office floor matts. This makes it perfect because you get the smoothness of a regular dance floor, but with the portability of… well.. plastic sheets.
You can lay multiple of them over an area (hopefully in front of a mirror so you can practice your footwork with your dance shoes – of course, without ruining your carpet. (Don't try high heels). Also, limiting yourself to 1 mat will help you get better at controlling your 'spread' which is the distance that your body moves when doing footwork. (Well, I call it the spread which is a investing (stock) term). That way when you are a club, you have learned how to do patterns, combos and footwork in very little space without hitting your dancing neighbors.