How much trusses cost depends on the quality, design, and pitch of your roof. Generally a roof truss will cost somewhere between $50 and $100. The total price of replacing a roof will depend largely on how many trusses you will need. Additional costs will include a permit fee, and labor costs. In many areas if you are a home or business owner and want to repair or replace your roof, you must obtain a permit. Generally this permit will cost between $25 and $50. Your labor costs will vary greatly depending on what company you hire to do the work.