How do you get all these spare keys for steam and GoG?
Some (or a lot) are spare bundle keys, from games you've already had. Others are games bought cheap that you afterwards decided you aren't going to play (thus try to buy your games as gifts whenever possible). A few other times it's through other beneficial trades.
Thank you for the information. I could not do it. I would be afraid to buy a game that everybody has and end up with a game I cannot exchange.
I prefer to wait for discounts and hope I will have enough on my b-account. I guess I am too romantic.