Towers has a global win limit of $200,000 per round. The maximum allowed bet is thus adjusted and limited based on the the difficulty mode chosen by the user. The minimum bet is set at 0.10 USD.
The maximum multiplier for Easy is ~34,5x.
The maximum multiplier for Medium is ~613x.
The maximum multiplier for Difficult is ~35,354x.
The maximum bet allowed is thus based on the above multipliers. For medium difficulty, the maximum bet is up to ~$326.20 per round.