I started in April this year, with a goal of earning $500 per month. I do mostly merchandising and theater assignments (because I enjoy them), and a few mystery shops (mostly FF and gas stations). Although I am signed up with about two dozen MSCs, the vast majority of my work has been for just three.
I have exceeded my goal every month, and find I am doing so earlier each month, with less actual work involved. As a matter of fact, I have already surpassed my goal for September!
What really helped me is that I was developed a good rapport with the scheduler for the company I work for the most. He always calls me when he has an assignment with a good bonus. In exchange, I say yes almost every time he needs something done last-minute.
Also, I did my first two arches when they were still in single digits, just for the experience. I loved the shop for its ease, but hate the food, and told myself, "no more." When I was called to do another, I expressed reluctance, and they offered a little bit more. Lather, rinse, repeat. I like to think I have earned my way up to the nicely bonused fees I am now offered.
I can't really say if it's what I expected; I didn't really know what I was getting in to. Six months ago, the thought of needing ONE (used) new tire for my car had me in tears. I don't know how, but I somehow came across this forum, and decided to cross my fingers and sign up for some MSCs. I know that $500 each month isn't a huge amount of money. However, it is a huge difference in my stress level and quality of life...the difference between having to ration food and being able to actually enjoy my life again.
I do know that I really enjoy the flexibility and variety of work.