bought these from amazon. they were just under $30 each. here’s the link
i was already using a usb-to-vga adaptor on my music pc and, with the help of a kvm switch (but only using the “m” of it) i was able to have my “main” pc’s monitor available as a second monitor for music stuff. now with the monitor arms my desk is much cleaner (i don’t have the ikea shelf brackets holding up the monitors any more).
seeing as though everything’s looking tidier i connected my keyboard to the kvm switch and so now there’s only one pc keyboard on my desk; even more tidiness