Rather join a gym than buy that, or get a bike. Getting out of the house is part of excercise... the fresh air will do you good.
I recently found a very good and healthy (I think?) way to diet. Before each meal down a glass of water. This will fill up your stomach and you'll feel fuller sooner. Be careful to do this if you have kidney problems though...

Don't let excercise be a drag to you... do something fun. There are small things you can also do if you're lazy like like me. While I shower I stand on my toes and go up and down the whole time, when I watch TV I sit on one of those big balls and try fun positions on it, this really helps with good posture. When I sit infront of my computer I do but clenches. I just clench and see how long I can hold it... eventually I forget about it and relax and do it again when I remember. I'm not a big excercise fan so I do the little things and it really halps me.