In May, he spent ~$208,000 on hats.
He spent ~$694,000 on t-shirts, mugs, and stickers.
He spent ~$120,000 on ads.
I'd consider hats, t-shirts, mugs, and stickers to be advertising. The $120k was for online advertising alone.
He's avoiding the "mainstream media", at least for now.
Hmm...
My thinking: As long as the people he gives them away to actually wear them, I'd consider hats and t-shirts to be a more sound investment than television advertising. Television advertising is both expensive - production and showing, and transitive - they're gone when you stop paying.
Meanwhile, hats and t-shirts can last for months and even years. I still have a Dan Sullivan(our senator) t-shirt in very good condition.
Another factor, I think, is that the media, especially the news, is currently giving him as much coverage as people can stand, in my opinion. Why should he pay for what he's getting for free?
As for his using his own companies for services - as long as he's donated more to his own campaign than what he's funneled, I don't care. It's likely that he uses his own services because they're the ones he's familiar with.