As playing slots for long, I have noticed that the chance of hitting the Bonus Feature of a certain slot game is much harder when there's a Buy Feature. Obviously, because they are pushing the players to buy the feature instead. Playing in a game where there's no buy feature, I most likely hitting the Bonus Feature.
If you just want to get bonus features then play slot games with pragmatic providers, there you will be able to get bonus features or scatters every 100 spins.
I have proven it very often, but you have to use or activate Double Chance which is at the bottom right of the game column for each round.
The chances of getting the bonus feature will increase, but this does not guarantee that you will get big win because in pragmatic games, large multipliers on normal rounds also appear quite often.
PGPlay (Pocket Games) game provider is one of the popular game providers currently as they are known for their stunning game graphics. There are online casino sites where some of their games do have a Buy Feature but not present on other online casino sites. For example, their game Treasure of Aztec do have a buy feature option on some sites but the same feature is not present here in the local online casino site that I'm using. I already played this game at different sites with or without the Buy Feature option.
It the same as the local site that I used to use, they don't have bonus buy feature in slot games but only rely on bonus features that actually appear erratically.
It just that on local sites the winning percentage is very difficult and that why I prefer to play on online sites with a crypto basis.