I have been using a portable laptop standing desk for a while but I also wanted a larger standing to use at home -- something that could hold my large monitor and the like. I didn't want to spend over $700 or need computerized memory settings that allow it to be put back down to seated position easily. I've heard of too many people just putting their desk in sitting mode from old habits. I also didn't want anything that was difficult to put together.
I'm sure I am not the only one to think of this, but what I decided to do was get a relatively cheap table with adjustable height legs from Ikea ($155). Then I extended the legs high enough for it to act as a standing desk. The table top was $35 and is by Linnmon and is 59 x 29 1/2 inches. The adjustable legs are by Gerton and are $30 each.
Since I knew from experience that I would not want to stand up all of the time, I purchased a comfortable swivel barstool with backrest ($140), from Living Spaces and is made by Moscato. I also found this really cool leaning seat called a Mobile Mogo ($99) made by the company Focal. It gives you the comfort of sitting but while you're mostly standing, which takes a lot of pressure off of your feet.
But I don't always want to lean against a human kickstand, so I grabbed this anti-fatigue mat by Stanley from amazon.com ($50).
Warning: I'm exactly 6 feet tall and I have the adjustable legs as high as they can go. So my desk is around 41" high. If you're taller, this won't work. Also, at this maxed out height, the table is a little wobbly so you won't want it if you want a completely sturdy desk. It's not too wobbly for me but if you have anything flimsy on your desk it will wobble somewhat.
Make sure to get a full height barstool and not a counter barstool. Mine is a 30" barstool, meaning the seat is about 30" high.
Because my desk is higher off the ground, some cables to my surge protector didn't quite reach. To remedy this, I put my power strip on my desk and inside of a little container made to hide it from dust and view. This cost $30 but was worth it to me, but you could probably easily make your own if you wanted.
Total price for everything (tabletop, adjustable legs, barstool, leaning seat, anti-fatigue mat, and power strip cover): $485. Just the standing desk: $155.