I'll probably spend a little over $500. I make a purchase almost monthly, and I did not spend as much as I had planned last year. Between Miniatures, Tiles and books, I'm sure that $500 is the low end.
On the other hand I just received the latest issue of the Pathfinder AP. Since it was the end of the Second Darkness AP, I decided to cancel that subscription going forward. I have more than enough 3.x adventures to choke Demogorgon, if necessary. After playing a few games with the Beta Rules, I have no interest in continuing with Pathfinder. Though I'll use all of that awesome material for 4e.
So I switched my subscription dollars to DDI, which I'm finding very interesting. I've already used the monster builder 2-3 times. I used the encounter builder to shave some time off in building a large encounter (think Mines of Moria). The writeup for Hestavar in Dragon this month was very interesting. And the arrival of the Character Builder topped that off. So I've already gotten more than $5 worth of usability off that subscription. I'm very pleased with that purchase.