So how do the programmers pay for their mortgages?

What exactly does this mean?

Who ISN'T fond of money? The computer you play on costs money, so you had to pay those who built it. Electricity that runs you computer costs money, so you had to pay those who generate and provide it. This game you play is free to play, but those who program the game and the hardware to run it costs money, so if you aren't paying for it, who is?