We're letting Amazon's AI shop for us: Buy for Me orders from brand websites, and Auto Buy requests set through Rufus or Alexa+ that buy when an item drops to a target price. How much can either one charge without asking us again, and how do we keep a real ceiling on it?

What should I check, step by step?

1. For Buy for Me, treat the Estimated Total plus $15 as the price you're agreeing to. If $15 matters on that item, open the brand's own site and check the price, shipping and tax first; Amazon's terms say prices shown in Buy for Me may not be the merchant's current price.

2. If you get Amazon's email or app notification that the Order Total is more than $15 over the estimate, read the new total before you approve it. Approving it is a new purchase decision at a higher price.
3. Before using Buy for Me, read the brand's return and shipping policy. The terms make the brand the seller and the purchase subject to its terms, and independent write-ups quoting Amazon's Buy for Me FAQ say Amazon's return policy and A-to-z Guarantee don't apply.
4. Keep Auto Buy requests few and deliberate. Each one is a standing order that spends without asking: add up the target prices of all your active requests, because that sum is what Auto Buy could charge if every price drops at once.
5. Prefer a fixed target price over a percentage. Alexa+ accepts requests like 'buy it when the price drops by 20%', which leaves the actual amount to whatever the price was when you asked.
6. Change or cancel requests you no longer want by asking Rufus or Alexa to manage them; a request can be cancelled any time before the order is placed.
7. Watch your email and Amazon app notifications for Auto Buy order confirmations, and cancel anything you don't want in Your Orders within 24 hours of it being placed.
8. Point the default payment method at a card you can cap or lock. Auto Buy uses your default payment method, so a card with its own limit or alerts is the one ceiling Amazon's settings don't provide.
9. If an AI assistant of your own is setting Auto Buy requests for you through Alexa+, require your approval for each new request rather than each order, since the request is the moment you can still say no.

How much can Amazon Buy for Me charge above the estimated total?

Buy for Me shows items Amazon doesn't sell, from brand websites, in the Amazon Shopping app. When you tap Buy for Me, Amazon's launch post says you're taken to an Amazon checkout page to confirm the delivery address, applicable taxes and shipping fees and payment method, and Amazon's agent then completes checkout on the brand's site with your encrypted name, address and payment details.

• The Terms of Use define two numbers. Amazon gives you an Estimated Total of the estimated price, shipping cost and taxes; the merchant produces the Order Total of the final price, shipping and taxes. You agree to pay an additional amount, as displayed in checkout, to cover the difference, and you're charged by the merchant only for the Order Total. If the Order Total is more than $15 over the Estimated Total, you get an email or app notification to review it and decide whether to buy at that price.
• The terms also say Amazon acts as your agent, the merchant is the seller and Amazon never holds title to the goods; that your purchase is subject to the merchant's terms (shipping, returns, exchanges, warranties) and to the merchant's confirmation; that Amazon gives the merchant your name, shipping and billing addresses, phone number and email; and that each purchase gets its own relay email address that forwards the merchant's emails to you. Buy for Me is only for customers shopping in the United States, and Amazon can amend the terms by posting new ones.

Does Amazon Auto Buy ask before it places an order?

Amazon's About Auto Buy help page describes it as setting a target price for an item: Amazon tracks the price and places the order automatically, with your default payment method and saved shipping address, when the price drops to or below the target. You get an order confirmation by email and notifications in the Amazon app and from Alexa afterwards, and a notice if the purchase fails, for example because of an invalid payment method, a missing address or the item being out of stock.

• The documented limits: Auto Buy is for Prime members only, only for items Fulfilled by Amazon, one active request per item, one unit per order, no promotional discounts or coupons, and up to 200 active requests at one time. You set requests in the Amazon app (the Set price alert button, or by asking Rufus) or by voice with Alexa+, for example 'buy this for me when the price drops below 100' or 'buy it when the price drops by 20%'.
• Cancelling has two windows: cancel the request any time before the order is placed, or cancel the order within 24 hours of it being placed, from Your Orders. The help page doesn't describe a spending total across requests, a cap per day or month, or a way to require a confirmation before each Auto Buy order.

How do you cap what Amazon's Buy for Me and Auto Buy can spend?

For Buy for Me, the per-order ceiling is the Estimated Total plus $15, and only the review notification above that asks you again. There's no documented setting to lower the $15 margin or to cap Buy for Me spending per week or month.

• For Auto Buy, the ceiling is the sum of the target prices of every active request, and up to 200 can be open at once. A request you forgot about still buys when the price drops, so the controls that work are keeping the list short, removing requests you no longer want and watching for confirmations inside the 24-hour cancel window.
• For both, the payment method is the backstop. Amazon's pages don't describe agent-specific spending limits, so a card with its own limit, alerts or the ability to lock it is what caps the worst case; if something does go wrong, Buy for Me orders go back to the brand under its own policies, not to Amazon.