according to the proverb gambling only make miserable, so I think if there is free use only, do not use capital and if you want to use a minimum use of capital
If you don't use capital then its not considered gambling because you are not actually risking anything. Its like playing Blackjack on your phone for fun, its not actually gambling.
But when you already know the end result then why you would want to spend money on gambling because if someone wants just to play for fun then it should be OK for them to try with free money what sites may give. Gambling is not a make money so one should always gamble with minimum amount to reduce loses.