You will never totally get rid of piracy. Pirates tend to fall into 3 groups, in my experience.
You have the people who simply find that it is more than they can afford, but would buy at lower prices, you have the people who pirate because it is easier (no DRM, etc), and then you have the people who would never buy at any price.
I'll admit that I have pirated before. There were a few times I pirated because of DRM. I remember when the game based on the 2003 version of the Hulk movie came out, I got it and due to a bug in the DRM I was unable to play it. Vivendi knew of the bug and refused to patch it. They actually ended up offering refunds to the effected people instead of fixing it. The pirated version had the DRM stripped, and would play fine. I didn't accept the refund, and played the pirated version. I've also pirated things when it was not available.
From studies I've seen, and anecdotes from various companies, when you have things that are cheap and easy to get sales will increase. 2d Boy found that roughly 82% of copies of their game World of Goo were pirated. They then started having sales, even one where people named their own price, and sales picked up. They didn't add DRM, because according to them, the people remaining wouldn't ever buy. When they ran the name your own price sale, they asked everyone who bought then why they chose the price they did, and 22% (the largest group) said they did that because it was what they could afford. Nearly 8% said that they were going simply legit. Also take a look next at iTunes. Here is an example of making it cheap and easy to get music, and sales have skyrocketed.
With the latter group, who never will buy, they also often have a pokemon "Gotta catch them all" mentality, where they pirate lots of things because they can, but most of the time never use it.
Pinch Media showed this in their study of iOS devices.
Now, if we forget about that latter group, we can see that having lower more affordable prices will get more sales.