I'm pretty sure Reddit used to be profitable. There used to be a bar on the right-hand side that showed how far each day's Reddit Gold purchases had gone towards covering the day's server costs. When I first started using Reddit, it'd typically be about a third of the way full when it reset, but a few years after the at, it was filling up after about eight hours, suggesting they were covering the server costs three times over, which should have left plenty of money for staffing costs as they didn't have many staff back then. Eventually, they got rid of the bar. Later, they did things that would have increased costs, like hiring people to make New Reddit and the Reddit App, and hosting images and videos themselves instead of leaving it to imgur, and I guess these were enough to make them no longer profitable and force them to aim for faster growth.
To go one better, there's http://isthereanydeal.com/, which tracks prices across a bunch of vetted key retailers (i.e. companies that buy wholesale keys from publishers and sell them to users, but not grey-market or dodgy sites) so you can see where's cheapest and get notified of discounts etc.
Why check GreenManGaming and Steam (and potentially a bunch of their competitors, too) when you could check one site and know who's best?
I've accidentally made this read like an ad, but they've not paid me to say this, I just always check the site before buying games, and have either saved loads of money by doing so over the years, or have ended up buying a bunch of things I'd have ignored on the grounds they were too expensive otherwise. I don't know in which direction, but it's definitely changed the amount I've spent on games over the last ten years.