I will give here some links, where you can buy games and resell them in Kinguin or G2A. Doing the same and making some profit. All games are in bundles, for some games you need to wait a little bit, that the price will be good for reselling them. There will be more guides how to make some money or games.
If you have more questions, you can write me to PM. When i will find more good deals, i will add here.