Mystery shopping can be a lot of fun. You get to visit new places, meet new people, and can make a real difference in the quality of service provided to other customers. You can enjoy free food, free products, and make a little cash on the side while contributing to the greater good.
It does take some time and effort to get started, and some mystery shops are much more enjoyable than others. Some companies are easier to work with while others are pretty impersonal. Some schedulers are great while others are demanding and not very responsive.
Try a few shops. If you enjoy the field, then you can stay pretty busy (if you desire) or can pick and choose depending on your own schedule and personal preferences. Mystery shopping is very flexible, and can be a good way to fill small or even large chunks of free time. Whether you enjoy a free meal every couple of months or like to have some spare change to help on bills, you can set goals and make your own mystery-shopping life work for you.