It depends a little on circumstance. Personally if it were me, I'd just buy a long-ish USB-C to HDMI cable (i.e. male USB-C one end, male HDMI the other end). If anything you need to use has a captive HDMI cable (or if you can't get to the socket to plug a cable in, and need to plug their HDMI cable into something, then a short USB-C to female HDMI adapter might be what you want.
The same things as most tech applies: you generally get what you pay for, so don't just look for the cheapest option. In terms of HDMI make sure it sys it'll do whatever resolution you want (i.e. 4K) at 60Hz, or it's gonna look terrible.