A local Track, A heavy bag and gloves, a jump rope, Plyos and agility drills ect... There are a lot of cardio excercises you can do if you are creative
For $300 I picked up an Eclipse HR1100 Elliptical machine from Sports Authority. I've used it 5 times a week since Thanksgiving and it has held up well. I weighed 255 when I got it. I'm down to 230 now.