I think he did like Paul and supported himself and preached at the same time. Peter is referring to household servants, domestic maids and butlers, as well as many others who were employees skilled in trades and professions. They were owned as slaves but they were often well paid. They represent the most common workers in the Roman world of that day. We can apply those same principles to the work place of today.
Christian employees are to willingly obey their bosses.
Too often I've heard of boss-employee differences when the employee thought he knew the way to do the job better than the boss. Even if the employee was right, the boss is the one who should have the right to have the job done his way. Sometimes we carry this over into our Christian lives. We want to tell God how we want something done. We're trying to help God do His job.