Mid-Roller casino bonuses are bonuses that are bigger than average but not too big for the average player.
For example a $500 deposit requirements, or any bonus you'll get that is above $500 will usually be targeting a mid-roller casino player. Do notice that sometimes even bigger bonuses than that can be considered as Mid-Roller bonuses because they require more than one deposit and that the deposits and bonuses will be done over a longer period of time.
The definition of Mid-Roller Bonuses is derived from their sums, meaning Bonuses which are not too low but not too big either. If we want to put these words into numbers, then in the criterion of Online Casino Bonuses, anything beneath 400% or above 600% could be categorized as not belonging to the range of Mid-Roller Bonuses, but this is not to be taken as a fact since there is no canon of Online Casino bonuses. The logic which places Mid-Roller Bonuses where it is by this definition, is that a 1000% bonus is pretty much the zenith of Bonuses, the classic High-Roller range, and anything beneath 400% can be impressive and fulfilling, but still a bar needs to be set.
Mid-Roller Bonuses usually come with requirements. These could be Wagering Requirements, meaning a demand from the Casino that you'll wager the amount you received within a specific frame of bets before you can make withdrawals in the Casino. Others set a minimum amount of the Deposit you are required to make in order to receive the bonus, or limit you to play only one specific game. Take the time to read the Terms before signing-up, you'll thank yourself later.