Last month was my first month (I signed up on April 2) and I have $100 in gift cards sitting here right now from that month. I have $25 in my account as of right now as well.
However, my mom and sisters signed up at the same time. The most any of them has made is more around the $15 range. I think in part it is because I go through and try to pick up any surveys I haven't already done for the day every few hours. By the end of most days, I have managed to get 5-12 surveys.