In order to get enough exercise, a gym membership is necessary.
I used to have that mentality, and any activity outside of the gym was somehow void and insufficient. It's not true, and it's a silly excuse. It really isn't about hours in the gym, and it took me a few years to realize that.
So, in no particular order, here are some things you can do at home, for free:
Walk: Until Roo came along, I wasn't really a fan of walks. Now, we walk at least 1.5 miles (at quite a brisk pace) each day. I look for new routes and extra hills each day to really get a good workout.
Stretch: This is such an important aspect of physical health that is overlooked by so many people. Spend time each day stretching yourself out. I had really tight hip flexors just five months ago, and I struggled to keep a fast pace when walking. Now, Brett can barely keep up with me when we're walking Roo, even though he towers over me. For some stretching examples, see http://www.thestretchinghandbook.com/. There are some excellent examples for sports specific stretching and it goes into great detail regarding anatomy and the science behind stretching.
Strength: Using resistance training is also really important, and again- often very overlooked...especially by women. It will NOT make you bulky, it will NOT make you look manly, and it's so so so good for you. If you're not doing any resistance training, now is a good time to start. Do you need weights? No. If you have weights, great. That just means you don't have to spend time getting creative. But if you're on a tight budget, and you have no interest in joining a gym or buying weights, here's a link I found to a full body workout that uses just your body. http://www.fitlink.com/Full-Body-Workout-in-45-Minutes.
Intervals: If you've been running outside, but haven't seen the weight loss you're looking for, look to intervals.You can do intervals with any cardio activity, it's simply about timing. For walking, check out http://www.the-fitness-walking-guide.com/interval-walking.html. For something a bit trickier, check out http://www.nowloss.com/advanced-interval-weight-loss-workout-routines.htm.
There's plenty more, but these are some great methods you can try today. GOOD LUCK!