My adjustable desk started with this: Monitors in front of tower PC when sitting. When I want to stand, I put my main monitor up onto my tower and get 4 empty shoeboxes which I use to prop up my keyboard and mouse to a comfortable height. I decided that if I really was into the whole 'standing desk' thing I'd prove it to myself by doing this, then maybe one day I could spend my money on a fancy desk, but only after I'd shown that I'd stick to standing while working.

It takes like 30 seconds to move my desk around, I'd be kidding myself if I could justify a $800 desk (if I could even get it in AUS) to save 30 seconds a few times a day