For profit internships

I have a small business that is set up as an SCorp. It is an online blog that is running in the red. In the past, I have had a paid editor/social media person and paid writers. I paid writers per article and the editor I paid a set rate per month. Was this legal? Also, I have had a lot of interest in internships with my company. Is there any way to legally set up an internship? It seems that the definition of an internship would make it not reasonable for most small business to absorb the soft costs, especially if the business can't receive a benefit from it. What about people who want to contribute articles to promote their business, websites and products? If they want to contribute for free to promote themselves, is that legal? Thanks