Depends on your needs. I grabbed a couple of Apple's USB-C to USB-A adapters for the odd occasion I need them, then got new cables for HDD, Camera, HDMI etc. Far easier for me. I also prefer the Apple adapter as it sticks away from the machine, so there's no stress or weakness on the connection.
Some people prefer to use a dock which has USB-A ports on it, again I don't really use anything other than an occasional memory stick so something like that is bulky to me. But there's plenty of multi USB-A adapters, or whole docks with various ports on it.
And lastly some people just replace all their cables. They're not much, and you can grab the few basic ones you need quite easily.
If you're after just a single USB-C to USB-A adapter, there's hundreds. Again personally I don't like several things jammed together for stress reasons, but they start at something like $5, so you can grab a couple happily enough.
I've swapped out all my old USB-A cables with USB-C ones. Most of them are just a few dollars. Never used a dongle on my 2017 MBP unless it is for HDMI.