Paying taxes on gross income

Well I have made a few calls around and to be honest! The lady that answered the phone for landstar was very nice and seemed to want to answer my questions! Now this is a what if question! I live in pa and if I was to do this I would like a ball park on the amount of taxes all the o/o on here take out on thier settlements! If you were able to make between 2500 and 3000 a week! How much do you take for uncle sam? 15% ,20% of gross! I called schneider at that was about a waste of time with that lady! My dog gives me better info! Maybe a foolish question to you all but I dont know much about this side of the business And I need to know before I make a any descisions! Thanks for your time!