It depends on the company he works for and the type of policy sold. I have seen commissions as low as 30& and as high as 120% of the first year premium This is paid by the insurance company, not you. Life insurance premiums are placed in an insurance company's account and a special fund (to keep this simple) is set aside to pay for any commissions and other expenses on a company level, not an individual policy holder level. Your premium is just a basis of what is paid out to an agent for his hard work and marketing expenses.
As a general rule of thumb. 100% of first year premium is paid out to someone as commission. It's not always your agent or "salesman" that gets it all. Many companies have several people that get a portion of the commission and your agent would only get his portion.
The commission comes from the insurance company rather than from you. Even if you purchase direct without an agent, you will pay the same amount.
Compensation to life insurance professionals differ in every marketing distribution channel. The three main channels are career system, independent brokerage and broker/dealer. Most career agents and broker/dealer registered reps who sell life insurance "average" $55,000 a year. Their independent counter parts earn about $70,000. The top 10% of life insurance sales people earn $250,000 or more (includes renewals.)
The commission comes from the insurance company rather than from you. Even if you purchase direct without an agent, you will pay the same amount.