Pinterest is awesome for inspiration boards, ideas, and just plain fun. They don't tell you NOT to pin your own stuff, in fact, the etiquette guidelines read as follows:
Pinterest is designed to curate and share things you love. If there is a photo or project you’re proud of, pin away! However, try not to use Pinterest purely as a tool for self-promotion.
pinterest.com/frannyp
I have a "paper crafting" board where I always pin my new cards I make, but I also pin ideas for cards and things from other people's sites that i like. I also have a board for my son's room, which I used to collect ideas and inspiration, but then I posted final photos of his room to it as well.
I think if you only pinned your own stuff, people would begin to lose interest in your boards and you would not be able to supply the large amount of photos/ activity that keep you at the top of the pinterest homepage.
As for people making detrimental comments about pricing, etc., you just have to think that at least someone appreciates your work and they are promoting it in such a way that someone who would be willing to pay for it might be more likely to see it.
Happy Pinning!
