I agree with what Cadpoint is saying. Talk to the GC and find out what % he marks your bill up. I would not let it be over 10% that way you know what is being presented. If you were to do $10,000.00 worth of work for this GC in a years time he will 1099 you for $10,000.00 and you can take it from there with your deductions. Let the GC worry about his own profits and taxes. Just keep up with what you billed him and what you received to compare it to the 1099 at the end of the year. If you bill him for $11,000.00 ( 10,000.00 + 10%) he could 1099 you for the $11,000.00 and say he gave you a $1,000.00 in cash. No way to prove he didn't. He has you bills. That will leave you paying tax on his 10%