Amongst the several things you listed above, I believe I can say I've had series of wins via online gambling.
You're right that there are lots of giveaways, offers and freebie offers online that'll wanna attract one to partake in them, but I'm not a fan of online giveaways and freebies, I'm a man that believe that to get something, you must give something, so that's why I do gamble sometimes, at least I'm risking something with expectations of something in return, rather than giving nothing but expecting something in return.