My current recommendation when I get asked that question is not to bother with any third-party AV and just use Windows 10 with Windows Defender (unless they're on OS X anyway). When I'm asked to set things up, I switch their default browser to Chrome (or Firefox for those who "don't like Google"), add uBlock Origin and use Click-To-Play for plugins (which, surprisingly, isn't much of an inconvenience once you block ads anyway). If someone asks for extra protection, I add OpenDNS Umbrella to the setup ($20/year for 3 devices), which is a nice additional layer of defense. Chromebooks are also a great option if someone's not doing much other than email, web browsing and such.
My other recommendation is to use a tablet for things like online banking. (Yes, even an outdated Android tablet is probably less likely to catch malware that will steal your money than an average computer.)
This is the first time I have heard of OpenDNS Umbrella. I just gave it a try (they have a free trial) and it's really nice--after some simple configuration you pretty much just set your router's DNS to OpenDNS and then your DNS requests are both monitored and lightly protected.
My other recommendation is to use a tablet for things like online banking. (Yes, even an outdated Android tablet is probably less likely to catch malware that will steal your money than an average computer.)