I love my Amy Dixon cardio workout. It is about 36 minutes and you do some of the exercises with dumbbells but you can start without. Once you feel you are ready to add a bit of weight you can hold soup cans (campbell's) or plastic bottles with water. That way you don't have to buy dumbbells if you don't want to. Then you can replace the water in the bottles with coarse sand.
Even with light weights the cardio is an awesome calorie burner, I end up being more sweaty than during Zumba, and yet very easy to follow.
I got it at Walmart. This is her DVD I have:
Clicky
I got it at Walmart for $4.