With a debit card, you can only afford what you can pay with real money you own. The chance of getting into debt is at 0%. If you use a credit card, you could get a prepaid credit card because you need to (f.e. for online payments). Same principle as with the debit card, but working as a credit card. I use this for years and have never regretted it. It lets you control your spending and you will never spend money again, that you are not owning.
After you get paid from your business or employer, first, shift some of that into your savings and retirement funds. After that, you pay your bills. You can then live with what is left. Of course, that money that you are paying first for you shouldn’t be too high. Just high enough so that you can live with what’s left.
Budgeting is really important, whether you are a minimalist or not. It sets your limits on how much you can spend for what. Setting a budget for everything you spend lets you define the money you will need to live, mentioned in the Pay yourself first paragraph above. There are tons of mobile apps for your smartphone, that lets you take control of your budget. Just to name one of the most popular and recommended ones: Mint.
The title says it all. As a minimalist, you will reduce your spending and with that, you will get more time available. If you can, just earn more money in that time and you will get wealthier over time.