If you're into the trendy seven-minute workout concept, Quick Fit is a new US$0.99 app that breaks down these exercises into easily digestible bites.
While there are free apps featuring this brief, but intensive workout, this one stands out from the rest with its clean design and its opportunity for expansion. Via in-app purchases, Quick Fit offers the chance to expand the exercise selection to target different parts of your body, such as your abs. One of the things I really like about this app is that there are clear demonstrations of the exercises being done as you're going through the steps.
Otherwise, it's similar to other seven-minute workout apps out there. You can keep track of basic workout achievements, workout log and your weight. Despite the variety of free apps out there, Quick Fit's design and expansions make it worth the $1 entry fee.