If you want to earn more money, it depends on your capital, the more money you have the more money you can earn . It's working like Proof of Stake. More money you owned will give more chance to earn huge money. I would like to suggest you trading is better. Gambling is too risky which you can easily lost your money very fast.
You might have a point here, it takes money to make money. But if you join in an campaign its your effort that is being paid by bitcoin or altcoin. Then with this you can save and have a startup capital and use this earning in trading. This is a good idea in my opinion and that is also my plan.
Also you can earn from social media campaign.
Trading can be profitable if you have knowledge and skills in trading. If you have knowledge and skills about cryptos then surely it will double or triple your capital. Anyway, you have to work hard for it to earn more profit.