I had no money to join a gym either, so I bought workout DVD's (I love Jillian Michaels 30 Day Shred) and started working out in the privacy of my own home. That combined with eating less calories and drinking lots of water (and I mean LOTS...I drink 3 cups of water as soon as a wake up) has helped me loose weight.
I've gathered from doing research online that doing a combination of cardio and weight training will give you faster results. If you have a lot of fat to loose, focus more on the cardio at first, but don't forget about weight training. And remember that when doing weight training, you'll be burning calories, BUT also gaining muscle, meaning you might not see a difference in weight at the beginning, so don't loose hope.