To track how many steps you take in a day, and how active you truly are overall, you can use a Fitbit. This activity monitor clips onto your belt or sits comfortably in your pocket and works throughout the day without you realizing it's there. It then syncs to a free iOS or Android app that tallies such things as your sleep patterns, amount of calories burned over time and steps taken on any given day. At the time of publication, Fitbit trackers start at around $60 and top out at about $100.
Get more information on Fitbit and its product lineup.