Actually was doing some research on this the other day for a friend and here's what I found.

Used:

• ASUS ZenScreen (MB16ACE) 15.6” - buy used for around 140$ USD on amazon maybe cheaper on eBay

• ViewSonic VG1655 15.6 Inch - buy used for around 120-130 USD on amazon maybe cheaper on ebay

New:

• ASUS ZenScreen (MB166C) 15.6" - currently limited deal of around 100 USD new. Its the best bang for your buck imo if you want to go with a known brand

I just got this one a few weeks ago. Only used it for 15 or 20 hours, but it seems good so far.

Sub 120 puts you in a kinda tight spot. Not too much more than 120 will take you from a garbage second display, to something extremely nice in no time.

Should the display be driven by USB c alone, or is a separate power brick taking up space acceptable? You say work related so I assume 60hz is fine, but are you looking for 14” 1080p, 16” 1080p, or something g higher res?

For $170 I got a 16” 2560x1600 120hz IPS display and I love it. Sadly they downgraded the model to 1440p but my friend has one and it’s still great.

Make sure the brightness at least matches your laptop's brightness. I made the mistake (twice!) or ordering the cheapest one I could find and they're both so dim compared to my laptops that they're basically unusable in anything but a dark room.

There are like 3 or 4 main body styles. pick the one you like the most and find the best price from any of the random Chinese companies on Amazon that has more than 100 reviews. They are all made by the same place, as far as I can tell. You are just picking the middleman.

The well known brands are not better quality or better service, and sometimes fewer features. Definitely not worth that $200+ price.

Hopefully you are in a place that gives you easy access to an Amazon return. There will always be a random item damaged in shipping or that is DOA. I haven't been able to find a high DOA in the random Chinese brands.

I like Acer 27" 1080p monitors in this price range. I got two for my wife's work from home setup a couple of years ago, no issues.

I picked up one of the ARZOPA ones and they are fine. Not the best looking, but good enough for a second monitor on the go. I used to take my ipad 9.7" with me places for this purpose and even though the image isnt as good, its way less effort to carry around.

I wouldnt use it as a single monitor regularly, nor for gaming.

I had to keep using the usb-c cable that came with it. Not sure if its a specific protocol that my thunderbolt 4 cables dont support or not. Minor inconvenience i havent looked into further.

Thanks so much everyone for your input. I ended up with a KYY K3. There was a lightning deal for it on Amazon for ~$90. It showed up yesterday evening and so far, it works just fine for what I need it to do. I'm certain it will help my productivity while working away from the office or my home set up.

Https://a.co/d/dFBQNzT

This might just be me, but I have an old iPad 2 with an app that lets you connect the iPad as a second display to your PC. The app is TwomonUSB, although I don't endorse it. There are alternatives like Duet Display.

An old iPad of any kind shouldn't set you back any less than $20 (or what you may have lying around), the disadvantage mostly being limited to the 10" size.

I got this last year and it has traveled up and down the East Coast, as well to the South West. Gone by plane and car. I have used it with my Surface laptop running Windows for work, my personal Framework 13 running Fedora Linux, and my Nintendo switch.

Is it great? I don't know, but it works.

ZSCMALLS Portable Monitor 15.6 Inch Full HD https://a.co/d/0Tx4km5

Let us know what you wind up going with.