In my case I used an 8 year old PC, fitted it with two network cards and a (free) copy of Untangle to handle my networking needs.
One of the network cards is connected to the ISP router, the other card is connected to a router/switch to which all computers in my LAN are connected.
A standard router/switch cost even in these parts of the world next to nothing aymore. And Untangle is very easy to work with, has a rather extensive administration possibilities, which can be accessed by a web browser (after filling in the correct password/username combination of course).
The 8-year old PC only needs a keyboard and monitor when setting it up (very straightforward), after that it can be run without monitor. This solution set me back around 50 USD, most of that was ´eaten´ by my choice in router/switch. 6 Years ago I could buy a Cisco 100MBit/sec router/switch with 24 ports and two years of use at an auction from the US embassy here in Paraguay.