Salary
Average Salary: $20,000
Expected Lifetime Earnings: $834,960
At $20,000, the average annual salary for this job is...not so great (source).
If you have this job, then you're most likely a college student or graduate trying to pay off your student loans as you pull your life together. The few people not in that position are probably looking for work elsewhere and are using the kiosk as temporary employment.
You can expect to start out with minimum wage—and probably keep that wage for the entire time you work there unless it's a more expensive and successful kiosk (like one that sells pretzels or iPhones or something). Even then, you're probably only looking at about ten dollars an hour (source).
Some kiosks pay by commission, meaning the more you sell, the more money you earn. This is obviously done to motivate workers to actually do something, since mall kiosks can pretty much be hit or miss businesses. However, the endgame is still the same—only about $20,000 a year (source).