For me, a reasonable gambling budget is 3 to 5% of my income,
3-5% of income to be the budget for gambling is reasonable and looks okay. You have made a good decision to set aside a quite small percentage of your income. I am sure, there are many other gamblers that have a bigger percentage of their income to be gambling budget.
How do you plan your gambling or fun budget?
I have no certain amount of funds to be the gambling budget. I have no fixed schedule for gambling, I just gambling when I have funds and I am interested in the gambling game. So, I set my budget for gambling randomly, but I make sure it is still a proper amount of money for gambling. I mostly gamble for fun, not to achieve a certain target, so the gambling budget is easy to plan.