I use this for my 24-27-24 monitor set up
Mount-It! MI-773 || Triple (3) LCD Computer Monitor Mount Adjustable Height, Articulating, 20 21 23 24 27 Samsung Sony Vizio ViewSonic Acer Asus Dell Sharp LG PC Monitor Screens, VESA 75x75 100x100, Black https://www.amazon.com/dp/B00FQSHRK2?ref=yo_pop_ma_swf
I have one of the triple monitor stands from mount it.. I've got a 29UM55 on one arm a dell u2414h in the middle and and 23" NEC monitor on the other arm until I can get a deal on another ultrawide but as it is it's pretty sweet and they probably make a single monitor version or you can buy it and not install the arms. It fits 2 29" ultra wide and a middle 23" monitor nicely.
http://www.amazon.com/gp/product/B00FQSHRK2/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
Ive modified it a litttle bit by making the angles bigger. I wouldnt recommend this desk and stand combo. The stands a clamp and the desk is glass....... Thats why theres a board along the metal frame to keep the pressure off the glass.
https://www.amazon.com/gp/product/B00FQSHRK2/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1 <- Mount.
All three of them are Asus, but the one in the center is an Asus ROG.
There are a lot of ways you can go about mounting monitors, I will try to give an idea of what is possible.
First off, if you want all 3 monitors on the same stand, you have to figure out if it can hold all of them. IDK how big your 4K monitor will be, but if its 27" or bigger you might have to get a stand capable of holding 3 27" monitors. Some of the triple monitor mounts only support 3 23" monitors. A triple 27" monitor stand is gonna cost at the very least 70$. You can get higher quality stands but some of them cost 200$+.
There are monitor mounts that clamp onto the back of the desk or just sit directly on the desk (which I don't like very much, because if you have a shaky desk, you will have very shaky monitors). There are some triple monitor mounts that are wall mounted, which means no shaking, and it looks really clean, like your monitors are floating, but they are harder to find.
Then there is the cheap way which is to buy 3 single monitor wall mounts and line it up all, which can be a little tricky, but you can get a single monitor wallmount on amazon for 10 bucks, so it just requires a bit of DIY. Remember the monitor in the middle has to be closer to the wall and the monitors on the side have to be capable of bending outwards so you have some curvature to your monitors and not just flat a flat line of monitors spanning across your wall.
I think you would be hard pressed to find a triple 27" monitor mount for anything less than 70$. For example I might avoid something like this because it doesn't look like it has much curvature to the arms. If it has arms that you can actually adjust like this it'll be better because you can curve the monitors inward more.
That's probably a lot of information but I just typed up what I know. :)
Im actually in America now just moved to California, so i brought it from amazon. Its this one:
http://www.amazon.com/Mount--MI-773-Monitor-Horizontal-monitors/dp/B00FQSHRK2/ref=sr_1_13?ie=UTF8&qid=1436424565&sr=8-13&keywords=triple+monitor+stand. However it looks like you can get something similar from aus ebay, but its pretty expensive compared to the american price.
If you really want it, you could use something like 'ship it to me' to get it from america, for possibly cheaper.
http://www.amazon.com/gp/product/B00FQSHRK2/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
The monitors are dell U2311H.