This depends greatly on quality of care and genetics and the like. I believe the average lifespan of a budgie with the care the vast majority receive (small cage, seed diet) is around five years, or less. I took horrible care of my first two budgies, and they both died after I had had them for four years. However, looking back at pictures, the one who wasn't lutino didn't have her baby bars, so I'm not sure how old they are.
I also have some cousins that had a budgie who lived for years, even though he was never let out of the cage and it was rarely cleaned. I think he was probably around seven years old by the time he died.
From looking around on here, the average lifespan of a budgie with high quality care and the like is 10-15 years.
My budgie is a year old as of last month, and hopefully he's still got a lot left in him!