Playing in a currency other than the one the game was designed around sometimes produces odd buy prices, like 98.4x instead of a clean 100x. This comes from stake rounding at the casino level, and over many buys the small difference can drift either way. There is a note on
https://thebonusbuyslots.com listing which operators round the feature price in the player's favor and which round it up, which I had never thought to check. Minor, but worth knowing if you buy a lot.