Budget ideas

I would like to start a budget system, is it better to save with an envelope system and a categorized budget with categories in place. Or should I rely on just one method? I have watched tons of envelope and budget you tube videos but they involve games and dice and several books. I am one income on SSI and don't have to worry about mortgage taxes HOA's water gas or electricity etc. My money is for car insurance, cell bill, tv subscriptions, car maintenance my every day etc. I want to budget a save some money in certain places some I can save something. The envelope system work but I need categories. I have about $300 left every month and I use that money to blow. I want a cushion to save for like trips events and etc, how do I accomplish this