Is there a cheap, common USB wifi dongle that works?

In the old days I kept a couple Realtek USB adapters around that would almost always work out of the box or with ndiswrapper

No need to get a USB dongle. You can use PCI passthrough to a Linux VM that has the Wifi driver.

See my comment here: https://news.ycombinator.com/item?id=47704816

I'd like to know more about what it takes to turn on PCI pass through for laptop hardware. On desktops and servers it's typically the IOMMU setting in the BIOS. Is that also commonly available on laptops?

That's insanely complicated compared to plugging in a USB dongle.

It's only complicated once, though -- at initial setup.

And that setup part can be largely automated: https://github.com/pgj/freebsd-wifibox

(The computer itself doesn't care much about the complexity. It's a computer.)

My approach costs $0 . You don't need to do the heavy lifting, Wifibox does.

If you've ever had to deal with usb hotplugging then no pci pass through is much simpler