Cheapish multiple monitor setup for a linux laptop with only one video output (without daisy chaining)

A DisplayLink adapter seems like the only thing that would have any chance of working. It would need this driver: https://github.com/displaylink-rpm/displaylink-rpm Further info about the driver is here: http://nothen.com.ar/en/support-for-displaylink-adapters-on-linux/ and here http://www.displaylink.com/downloads/ubuntu
These are some adapters that might be able to be used: http://www.displaylink.com/products/find?cat=3&usba=1, but note that they have to be from one of these four device families (as per displaylink-rpm@github):

• DL-6xxx
• DL-5xxx
• DL-41xx
• DL-3xxx
• USB-to-VGA ($30; DL-165): https://www.amazon.com/gp/product/B004D0QC0A (DL-165 chipset is not one of the ones listed above, but multiple reviews from 2015 said it works with Linux, and DisplayLink says it's supported by the open source udl driver) and ArchWiki says it should work out of the box.
• USB-to-HDMI ($49): https://www.amazon.com/dp/B01C6HBJOA. Also Plugable. Also no official support for Linux, but one review confirms it works on Ubuntu. Only drives 2560x1440.
• USB-to-HDMI ($55): https://www.amazon.com/gp/product/B06ZYN4MC7, but is from some knock-off brand (Wavlink)
• USB-to-HDMI ($60): https://www.amazon.com/Plugable-Ultra-High-Definition-Graphics-Multiple-3840x2160/dp/B00NQCFXGA/, but no official support for Linux
• USB-to-HDMI ($65; DL-5500): http://www.diamondmultimediastore.com/bvu5500H-video-adapter-4K
• USB-to-HDMI ($65): http://www.dell.com/en-us/shop/accessories/apd/470-abhh?c=us&l=en&cs=19&sku=470-ABHH&baynote_bnrank=0&baynote_irrank=1&~ck=dellSearch (the one referenced in nothen.com.ar above; should work and has vga and hdmi outputs)
• USB-to-Dual HDMI ($75): https://www.amazon.com/dp/B075HMWLJF/. One review confirms that it works on Ubuntu, but no official support for Linux.
A monitor mount of some sort is also required. This one would likely work with a couple of cheap Acer monitors (assuming they have Vesa mounts on the back, which the S271HL does): https://www.amazon.com/VIVO-Monitor-Mount-Adjustable-Screens/dp/B009S750LA
Having more than one monitor (with Vesa mounts and that is flicker-free) would probably also be needed to do multiple monitors. 24" may work better than 27" for vertical viewing. Dunno.
Here are some 24" options:

• Dell E2318Hx ($120): https://www.amazon.com/Dell-23-Inch-LED-lit-Monitor-E2318Hx/dp/B06Y45V625/
• Dell S2415H ($150): https://www.amazon.com/Dell-S2415H-24-Inch-LED-Lit-Monitor/dp/B00M9B3XZW/

Here are some 27" options:

• BenQ GL2760H ($148): https://www.amazon.com/BenQ-GL2760H-27-inch-Response-Monitor/dp/B00IZBIMLK
• ViewSonic VX2757-MHD ($179): https://www.amazon.com/ViewSonic-VX2757-MHD-FreeSync-Monitor-DisplayPort/dp/B01A0ZRRCI
• Asus VN279Q ($199): https://www.amazon.com/ASUS-VN279Q-1920x1080-DisplayPort-Monitor/dp/B00DX64DCY