Originally Posted by
nachosdelux
If I remember correctly, you have to wait about 1 hour for pre-paid AMEX to work.
I once called Amex Customer Service and asked this exact question, as my card did not work after about 30 minutes. Guy went away, came back, and told me 70 minutes.
Costco is a great place to use up the last bits on a prepaid Amex. I use them until they get down to $10-20 and take a stack into Costco and zip-zip-zip, they are all burned up. I think I used 7 once.