Surprisingly - two non-adjustible sturdy desks works out cheaper.
Yes this works for many people, but there's several issues with this:
1. You need more real estate to place 2 desks, not everyone has the space in their home or office.
2. Finding that perfect ergonomic height become a chore when you have to prop something under each leg of the desk - and that's - if the desk is too short. If the desk is too high, then may have to saw the leg or resort to any other labor intensive activity. With an automatic desk, you just press a button.
3. If you have monitor(s), keyboard, mouse, etc. When you transition from sitting to standing or vice versa then you have to move everything over one desk to the next. That becomes annoying after a while, unless you just use a laptop. The problem with a laptop, is you only have one screen and its horrible for your neck posture and may lead to shoulder and neck problems in the future.
That said, in the beginning use whatever works for you to stand, whether it be 2 desk setup or simply a cardboard box on top of your desk. The mail goal is to get off you duff and stand more. Use whatever tools you please
My next thought was to look into kitchen mats as line cooks tend to stand for long periods of time.
I have the $60 one from Amazon, a step down from what Wirecutter recommends, but I think I will upgrade. I can generally do 4-5 hours standing with this: http://www.amazon.com/Imprint-Comfort-Nantucket-20-Inch-Cinn...
Unfortunately, the CumulusPro is out of stock everywhere, but I found you could order it online at a significant discount on Costco ($69 vs $115). Here's the link.
http://www2.costco.com/Browse/Product.aspx?Prodid=11762518&w...
1) You should ease into it - go from one hour to two in a week, two to three in a couple of weeks
2) GET Anti-Fatigue MATS to stand on otherwise sustained standing is going to Screw-up your legs
3) Have a stand-by(!) sitting desk and alternate between the two once you "get tired" standing
4) Don't be afraid to say "This does not work for me". A colleague who tried it with me hated to say this, but she was in constant knee pain standing up but would not go back to her sitting desk.