TLDR version: I bought this for $3.09 at Sears.
Saw on Google Shopping that Sears has it for 23.97. Went there with the physical ad from the paper. waited around for 10 minutes to get a person in electronics. Showed him the ad, he called the manager, manager instructed him to call Best Buy, he called Best Buy and asked if they had it and what the price was. They told him that they had one left for Xbox 360 and that it was 9.99. They asked him if this was a price match, he told them no and they told him they would hold this for him, he told them he'd "be right there to get it".
Sears doesn't just price match, they match + give 10% of the difference between the two prices! So that was another $1.40 off. Plus today they're doubling shop your way rewards points. I had $2.75 worth which was doubled automatically to $5.50 off. $3.09 + tax was the total.
Some Sears stores in my area have Darksiders for more and some for less so the "price match guarantee" 10% extra off may differ by location.
Why is everyone wanting a copy of darksiders? Is it getting rare?
Because it's supposed to be a relatively good game and it's very cheap. Darksiders 2 comes out sometime this summer.