The question everyone asks and nobody answers honestly. Here is the real answer based on game type and the bankroll that gives your strategy time to work.
The fundamental rule
Only deposit what you can afford to lose completely. If losing this amount would cause real financial stress it is too much. Crypto gambling is entertainment funded from entertainment budget — not savings or investment capital.
Minimum deposits by game
Crash (1.5x auto cashout, 1 USDT base): Minimum 50 USDT.
Blackjack (1 USDT base, basic strategy): Minimum 40 USDT.
Roulette (1 USDT base, D’Alembert): Minimum 50 USDT.
Dice (50% probability, 0.5 USDT base): Minimum 30 USDT.
Slots (1 USDT per spin): Minimum 30 USDT.
The deposit formula
Calculate as: (base bet size) x (minimum bets for strategy) x (number of planned sessions). Example: crash at 1 USDT per round, 50 rounds per session, 3 sessions = 150 USDT deposit.
Only increase your deposit size once you have demonstrated near-breakeven results over at least 5 sessions.
Start at Roobet with a small first deposit — no minimum threshold and lowest minimum bets.