I spent $1,100 on a GeekDesk max (including shipping). An investment in my health was long overdue, especially since I've spent $4-5,000 on my computer setup. The huge benefit is not having to move all your stuff whenever you're done sitting or standing. I press a button and in 10 seconds it's changed height. MAGIC! I highly suggest them to anyone, just watch out for the long backorder. Mine took 3 months to get here…
That out of the way, $1,000 for a good desk is a bargain in the long run. I'm so much more productive when I can switch between sitting and standing on a whim.