I'd rather spend those $100 to buy free spins / bonus rounds with sticky wilds on certain slots then having 1000 times rolls at $0.1 though. 
Some slots enable the option to purchase the bonus rounds instantly example of it would be The Dog House Megaways from Pragmatic Slots
Oh really, but can you buying the free spin from third parties casino like "Roobet" or need to play directly to the provider. Some slots enable the option to purchase the bonus rounds instantly example of it would be The Dog House Megaways from Pragmatic SlotsSome slots have that kind of feature though but of course it is not guarantee that you would get more in the bonus rounds compared to the amount that you spend to buy those bonus rounds
Here is an example of how it looks like from The Dog House Megaways and Deadwood Slot
Again, there is no guarantee that you might hit high multiplier during those bonus rounds but it could be so much more exciting than to do 1000 times autoroll and wait for those bonus rounds to appear . Warning, this could be highly addictive so set aside few budgets that you could risk to spend on this kind of stuff