At the risk of being a killjoy,
With any gambling, there's only ever one real winner, and that's the house. Be that the bookies, fruit machines, the lottery, dogs, online poker. There's big money to be had, but not by the vast majority of players; if that weren't true, they'd not be in business.
I'll drop a couple of quid into a quiz machine here and there, not with any expectation of winning but because I enjoy the games. I've been known to buy the occasional lottery ticket and take part in office sweepstakes for, eg, the Grand National. But you should only ever bet what you can afford to lose, if you view stakes as dead money then if you win it's great and if you lose it's no big deal.