You're welcome...btw..I'm also curious what the result will be. For me pinterest seems kinda hazy and overcrowded, but hopefully it will increase the visibility of my "artworks"...since now I'm an "artist" too. And my policy is to "follow back" any of my followers.
I did not invest lots of money so you might take my results with a grain of salt.
Selling Art online is not easy. A Metal Print for $350 is no impulse buy. A T-Shirt for $24 or a greeting card more likely. This is the reason why most ads that have a direct link to a print or product rarely work immediately:
The person that buys the Metal Print will most likely save the pin into one of her boards first and might come back after a few weeks. So how will you know that it was your promoted pin that led to the sale? You will know if the target site supports the Pinterest Tag (no POD does this so far).
For inexpensive items, this kind of ad might work but will be too expensive in the long run.
One of the ads for my Pinterest Course worked quite nice because I used advances features like an actalike audience. The (few) ads for my art did not result in sales -- but in lots of repins (the same thing as Joy reported in her post above).
But: As I did run traffic campaigns I only paid for clicks (to the Artist Website). All the repins are for free! And who knows what will happen with all of them in the future :-)
Summary: you have to know what you are doing, otherwise you may just waste your money with ads.