So if you already have a monitor (HDMI or DVI -- forget others), USB keyboard & mouse and $100 you can have a desktop Linux that is now (with the new ARM7) very responsive. Still no Adobe Flash support but otherwise...
What do you need?
* Pi 2 $35 (?)
* 16gb micro SD $25
* Wifi USB plug $15
* Powered USB hub (more ports + power for the Pi) $20
* HDMI cable $5 (or HDMI to DVI: $25)
* Case for Pi $10 (and up)
Most of the apps PC or Mac users are used to will be available with Linux, but with different names & they will be quirky. Here's an analogy with hiking trail difficulty: out East where it's fairly flat they use these terms--
Changing to Linux has to be a 2.5, at least.