Newbie Question? help how to price

[roofs]

hi yall i am in tn just starting my business. i clean roofs, but i have a pressure washer also a townhouse community wants me to bid on cleaning a brick fence that is 4ft tall by 150 yards long only one side i am going to spray it first with my cleaning stock then pressure wash it. i need to know what to charge them please let me hear some quotes thanks robert or you can call my cell at 615-389-9148 its sprint thanks again