For non-geeks, here's the sizing chart.
Stick PCs: $35 ish, thumb sized, tiny but virtually no ports or options. Tend to suck or have heat issues unless very simple useage, usually just male HDMI port
PC on a card : $35 ish, deck of cards sized, plus needs $30 worth of stuff to be useful. Basically slow PCs. Usually has 2-4 USB ports, and female HDMI port
Small box PC : $100 ish, Roku sized, generally has wifi/bluetooth built in, can typically handle slightly more load than single board PCs.
Barebones Mini Computers : $100-200 ish, book sized, Intel Atom usually, usually just need RAM and hard drive. Smallest thing normal people would think as being a PC
All of them is a different point of cost vs capability vs size chart. I was eying up Roku sized small box PC that'd be running Android and/or Linux. Since I had a single board computer, I'll give it a shot. Otherwise, I'll throw the dice and buy either a Roku sized PC or a barebones book sized PC.
Ben, problem is, the barebones book sized PCs got expensive due to lower demand. These days anyways. If I scour the jungles on Chinese electronic manufacturers, I'm sure I'll find something that'll work in that price range.