With discount stores popping up all over the place, it is quite easy to get some basic equipment for little investment. Amazon is a great place to look, but so are TJ Maxx, Marshall's, Ross, and the like. Here is an example of a very inexpensive home set up:
Yoga mat: $8
Kettlebell: $10-$15 depending on the weight you want. I like these vinyl ones for indoor work...they make fewer dents in the hardwood and that makes for fewer 'oh crap, gotta hide that' moments.
Dumbbells: $5-$25 depending on weight and type. If you go to one of the discount stores, you can easily find vinyl weights ranging from 2lb to 5lb. a store like Sports Authority or Dick's will have a much wider selection where you can choose what fits your budget best.
And now for a workout with your new gear. Repeat the entire circut five times. Seven if you're a badass.