What type of router mode do I need?

    I have a router that connects to my cable modem and I've got dual bands for WiFi. I have a computer that I am unable to install a wifi dongle so I need to use the ethernet port. I was using one of those through the wiring routers that had two boxes that connected the router and the other ethernet computer through the home wiring. It is slow. I just need the other computer to have internet access and not access to other PCs on the network. What type of router do I need and what mode: WISP, Wireless Bridge, repeater, something else? Cheaper the better.

    I use an Apple Airport Express WiFi basestation in Wireless Bridge mode for development as it means I can just connect an Ethernet cable and whatever board I'm playing with gets an IP address without having to muck about with WiFi drivers or configuring a connection. The last one I purchased (admittedly a couple of years ago) was about $20. It's not a blistering fast wireless connection, but it's "fast enough" for streaming moderate bitrate content for LE box/board testing and means I don't need to run a cable through three walls.

    TL/DR; any bridge device, or any router that can be configured as a bridge, is what you need.