Whether you’re shopping for Father’s Day or trying to keep your kids entertained over summer break, you don’t need to spend a fortune to get a great Fitbit right now. You can currently pick up the Fitbit Charge 6 for $50 off at Amazon , Best Buy , and Target , the Fitbit Ace LTE for $80 off ( Amazon , Best Buy , Target ), and the new Fitbit Air ( Amazon , Best Buy , Target ), and all come in around $100. While all three cost about the same, they’re designed for very different users. The Fitbit Air is geared toward anybody who wants a simple wearable focused mainly on health and fitness tracking, without the distractions of a screen or smartwatch features. It’s lightweight with no buttons, and tracks activity, steps, sleep, as well as core health metrics like heart rate and nightly blood oxygen levels. It also supports Bluetooth connectivity with certain gym equipment, allowing you to broadcast your heart rate to compatible machines during workouts.…