Depends on the degree of renovation. New appliances? New countertop? New cabinets? New flooring? New windows? And so on.
Often, it's in the range of $25,000-$30,000. But I was watching a TV show the other day (HGTV--entertaining, but you can't take it seriously) that threw out a figure of $12,000. On the other hand, I've known people, even in just "nice" (not luxury) homes spend $40,000 or more.
Hope that helps.