The stake limit can change based on the sport or market you’re betting on. The minimum bet also depends on the currency in your account. For example, if you're using Euros, the minimum bet is EUR 0.10.
There isn't a set maximum amount for bets overall. If you try to place a stake that exceeds the limit, you'll receive a message indicating the maximum stake allowed for that bet at that time. This means the stake shown at that moment is the highest you can place on that selection. If you run into this issue, you can simply try again with a lower bet amount.