Lead_carrier once bubbled...
Are you kidding??? Those are as rare as finding gold coins on the ocean floor. It can happen but it ain't likely. If you work as a DM for a shop you can usually get free air, and a few extra perks but that is a LOT of free air to make up the cost of professional fees and insurance. You can deduct your professional fee and insurance but you must report income and that does include barter and trade. Is the cost worth it? Sometimes yes, sometimes no. Only you can make that choice. Good diving