Often... but only lotteries that are sold offline are the ones I participate in more often, if you know HK Pools then every 11 pm (GMT +7) I wait for the numbers to come out. Actually there are also online platforms that handle this, but I prefer offline stores because we can more freely get updated information about whatever is happening around us when we are with other lottery buyers.
When buying numbers, there is not much to expect, because we are all aware that the chance of winning is very small... that's why the winner will simply get a high multiplier because the risk is very high. To minimize the risk, many people buy more than one ticket...
What if, I get a chance to participate in a lottery without any investment?
If any gambling site offers, free of cost entry in the lottery, i would definitely not miss that one.

I doubt that... if a platform gives free lottery tickets to its users, chances are those users are loyal and have made large transactions. Yes, we definitely understand the importance of special treatment because many gambling platforms also implement a VIP system too...and I think there is a mutually beneficial relationship between loyal gamblers and the platform, so it is very possible that there are free lottery tickets there