I love games like this. If they have a pay to win shop, that means that they're free to play. So you can play for free and drag through the game, or 'buy' the game. :P
I don't use a gaming chair for two reasons. One being that I have a nice comfy office chair. Two being that I never play console games, and I feel that gaming chairs are mainly for consoles. :P
The computer you buy must have pretty bad hardware. :( My old computer could run Roller Coaster Tycoon no problem and it wasn't that good. I recommend you going to bestbuy or a computer store near you and asking them to build you a decent one.