The subjectivity of product pricing

I went out today and picked up a presentation remote thingy (that's the technical term) today, and the pricing for these thing seems totally bizarre. It lists on Office Depot's website at $40, but in the store it was $90 and I didn't feel like seeing if Office Depot would pricematch what amounts to itself. Because this more than two-fold difference in pricing annoyed me I decided to shop elsewhere, and then wandered over to Future Shop to look there.

The price listed on the shelf at Future Shop for the same model was $50. It turned out that the product was on sale for $30. I just noticed that the Future Shop website lists the product at $68. After all this, what I'm left with are a total of 5 different prices (from only two stores!) for the same product, but no two any closer than $10. How do they determine pricing these days?