It's been almost 2 years since I built my standing desk at work. I built it with parts available from IKEA:
VIKA AMON tabletop - $49 (you could also use the VIKA BYSKE tabletop)
VIKA BYSKE adjustable legs - $20 x 4 (these go to a maximum height of 42 inches. I'm 5'8" and I keep mine at 41 inches)
HUGO bar stool - $119 (no longer available. The GLENN bar stool is similar and cheaper)
From Amazon: Anti-fatigue mat $25 (a rubber mat for standing on to reduce fatigue)
I didn't switch to this setup because I wanted to stand all day; rather I wanted to avoid sitting all day. With my standing desk, I can choose multiple working positions: standing, leaning, sitting, standing with one foot up, etc... When you sit, you're limited to one posture; when you stand, you have more flexibility.
Furthermore, there are health benefits to a standing desk: studies have shown that sitting at a desk all day causes a number of health problems, and that folks who use standing desks burn more calories.
It's been great, and I'm not going back. I genuinely have more energy with this set-up. I find I'm able to maintain my focus throughout a full workday.
I also feel less stuck. When I was sitting, I would continue sitting, even if I wasn't accomplishing anything productive. Now, if I find myself stagnating, I can step away and do something else: I go make a pot of coffee, or do some stretches.
The VIKA BYSKE set-up is not for everyone. First: you'll have to be fairly short to use the legs (they have a max length of 42"). Second: the table can be quite wobbly if it's not anchored to the wall (see a video of me shaking my desk here).
I know a lot of people that made the switch, but quit shortly after. If you're going to switch: be prepared for a transition period. There are 3 keys to success at the beginning:
Purchase an anti-fatigue mat and a bar stool. Don't skip this step!
Take it easy: don't try to stand the whole day! Use the bar stool to sit and lean on, and give your legs a break.
Raise your monitor off the desk. Again: I'm 5'8 tall. My desk is 42 1/4" high. I raise my monitors an additional 6-7 inches off my desk. Here's a good diagram.
