It is normally 3% to 5%. You need to make sure you read the contract and know how it is stated whether you are getting it net or gross. Plus, if it is net you need to make sure it is BEFORE they take out for all their expenses. Because if they are not wanting to treat you fairly they can claim all sorts of expenses to the point that it shows that they made no profit at all. Some companies will try and put you in the mix with all their other products so that if one of them shows a loss yours will help take up the drop and balance them out. This is great for them, but bad for you.
So, as I always preach READ before you sign!