If you are thinking of doing this as a side hustle, think again. Unlike some sites, study opportunities are few and far between. However, they pay very well for the amount of time/energy they require. Payment does take a long time, I didn't entirely believe it was going to come but I was just paid for a bunch. If you just like doing surveys, this is a nice way to make some easy cash, but it's not going to significantly help you financially.