In general the main remuneration on these type of policies is 90% in the first year and 3% after that. This can also increase depending on the insurance company and the amount of business placed with a particular company or other schemes that may be in place. For terms shorter than 10 years this would be less usually10% per annum up to 90% initial.
This would be considered the standard I guess but you will also pay the same price (and sometimes more) if you go direct to the insurance company yourself. Some brokers will also work on a fee only basis and may in certain cases refund any commission to their clients depending on what arrangements they have in place.
Either way there is still value to be got by shopping around in many cases. You should ensure that you are matching like for like if you are going to compare a policy on the basis of price and ensure that you are well covered for whatever you need. Your broker should carry out a quick "fact find" which should include information on salary, dependents, any loans, mortgages, other income, expenses etc. - a quick overview of where you are now. From this they can find out how much cover you (or indeed your dependents) need and make recomendations based on this.