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Digital envelope system: a modern take 
If psychologically there is no difference to you between cash and debit (you should test this over a couple of months on yourself and spouse to make sure), then I suggest two debit cards (one for you and spouse) on your main or separate checking account. If you use Mint you can set budgets for each category (envelope) and when a purchase is made Mint will automatically categorize that transaction and deduct that amount from the correct budget.  For example: If you have a "Fast Food" budget set at $100 per month and you use the debit at McDonalds, Mint should automatically categorize it as "Fast Food" and deduct the amount from the "Fast Food" budget that you set.  If it can't determine a category or gets it wrong, you can just select the proper category. Mint has an iPhone (also Android and Windows phone) app that I find very easy to use. Many people state that they don't have this psychologically difference between spending cash and debit/credit, but I would say that most actually do, especially with small purchases.  It doesn't have anything to do with intellect or knowing that you are actually spending money.  It has more to do with tangibility, and the physical act of handing over cash.  You may not add that soda and candy bar to your purchase if you have visible cash in your wallet that will disappear more quickly.  I lived in Germany for 2 years before debit cards were around or common.  I'm a sharp guy and even though I knew that I paid $100 for the 152 DM, it still kind of felt like spending Monopoly money, especially considering that in the US we are used to coins normally being 25 cents or less and in Germany coins are up to 10 DM (almost $10) and are used more frequently than paper.