How to limit the amount a vendor can charge for a purchase?

[WindsurfMaui]

How can I limit the amount a vendor can charge me for a specific purchase? I don't want a vendor to send me a order confirmation with one amount, and for Paypal to send me a confirmation that a specific amount will be billed to my account. Then to see a different amount is listed in my Paypal activity log.

This happened on my lastest purchase. Now it hasn't been charged on my credit card yet, which is unusual because once a purchase hits my Paypal account it usually shows up as a hold in my bank credit card. But this time no hold has been placed. But in general I don't want any amount to be charged to my account that is higher than what I agreed to in my initial order. How do I set this limit?

[WindsurfMaui · Accepted solution]

I tweeted Paypal and they asked me to DM them and I laid out the issue. It took a few back and forth tweets before I finally got the policy. No Paypal doesn't either notify customers or stop a transaction that bills more than they were cleared for during the check out process. 

But on the good side there is a limit to how m the uch Paypal will pay above the checkout amount. The limit is 15% with a hard limit of $75. So if someone is trying to rip you off or just makes a fat finger error and adds a zero to the amount you are protected. (Not sure how Paypal notifies clients when this happens but I hope they will send an email.)