Private payments

Cards

• Virtual card numbers are the best single upgrade. Many banks and services issue a unique number per merchant, with a spending limit, that you can kill without replacing your real card. A leak from one shop then affects one number.
• Cash is still the only genuinely untraceable everyday payment. Unfashionable, unbeatable.
• Prepaid cards for one-off purchases you'd rather not have on a statement. Check the fees.
• Apple Pay and Google Pay are a real privacy improvement over tapping a card, because the merchant receives a token instead of your card number. The wallet provider still sees the transaction.
• Skip loyalty cards, or sign up with an alias and a junk phone number. Supermarket purchase histories are sold and are startlingly detailed.

Payment apps that publish by default

• Venmo — transactions have historically been public unless changed. Set the default to Private, and set past transactions to private too. People's therapists, dealers, and affairs have been found this way.
• PayPal — check what your profile exposes; your name and sometimes address reach the seller.
• Cash App and Zelle — less public, but tied firmly to your legal identity.
• Splitting apps — a shared expense log is a record of who you were with and when.

Reducing what merchants keep

1. Guest checkout instead of an account, where possible. No account, no stored history to breach.
2. Don't save cards on sites you use twice a year.
3. Use an email alias per merchant so a leak is traceable and disposable.
4. Give a real address only when something physical ships. Digital purchases rarely need one; a parcel locker or work address works for the rest.
5. Opt out of data sharing in your bank's privacy settings — most sell or share transaction data unless told not to, and the setting is buried.
6. Check statements monthly. Privacy aside, this is how you catch fraud early.

Subscriptions

Virtual cards solve the other subscription problem too: a card you can cancel unilaterally ends the “call us to cancel” game without cancelling your real card. Keep a list of what recurs and audit it once a year — you'll find something.