Everyone has given great answers. For my home clients, I use JC Bands, Super bands, regular resistance bands, medicine balls, large furniture movers (can get from your local hardware store) and jump ropes. You might have to shop around for the best prices on all of these items but you can start here at www.performbetter.com.
I think the best equipment to spend money at, is a Personal Trainer. Many people buy equipment for their homes, but almost all of them quit using them after some time either because they don’t see any results on their own or lose their motivation. A trainer will help you reach your goals in a more effective and efficient way.
We all know the biggest problem is that clients stop working out. Therefore, the best home exercise equipment is the one the client is most likely to use. Here’s a bunch of good stuff: http://www.treadmill-world.com