Most online casinos establish the minimum deposit limit of $5, $10, $15, $20, or sometimes higher up to $100.
Note that it may not be expedient to deposit penny money due to fees that eat the lion’s share of the deposit. In this regard, make sure to check the fees in advance and find out how much of the initial amount will actually be credited into your account.
Last but not least, note that withdrawal limits set by the casino may not coincide with the deposit limits.