1) I have little to zero knowledge about hardware/software and I've gotten a very good PC, took me 10 min. of googling to see what I should get, pros and cons etc.
2) hook up your HDMI cable from your card to a TV
3) same as 2, you can even plug a controller to your PC if you prefer that, there are receivers for multiple controllers too
I guess you could consider the selling thing a plus if Steam didn't have sales where you get games for 5-10 $/€, otherwise what sane person would pay 60 for a game that they are planning to play once/twice then never touch again?