'From time to time I may have access to items that I am able to purchase at a lower price than retail, that I am able to resell for a small profit.'

And you can scream and shout that you are not a business seller but that doesn't change anything because it's there for everyone to see.

By not registering correctly, you are breaking the law. Just because you pay your taxes, it does not exempt you from not abiding by business regs and the laws which are there to protect the consumer.