Payments Standard works with your PayPal id and not an API set of credentials. With Payments Standard you will not stay on the site, you will be taken to PayPal to complete the transaction, then you will be sent to the page that PayPal returns you to. You will not know the status of the transaction at this time. You would need to rely on an IPN page to handle the information about the status of the transaction.
The client did sign up for a business account (free) with paypal, and I was able to obtain api credentials for the account, which I have put into the globals file.
There seems to be a difference of opinion between yourself and Jason Byrnes on whether or not clients can use paypal express for free? Jason has stated in numerous threads that paypal express can be used for free (which is what I am hoping for) but it sounds like your experience has been that paypal express can only be used if the client has subscribed to the monthly fee-based paypal pro?
I'm going to play with the idea that it will process through paypal exress using the globals settings with the api credentials. I figure I won't receive an answer to this post until Monday, so I will see what happens between now and then.
However, in the event that I cannot get it to work this way and I have to revert to paypal standard, using simple login id and password, and changing/doing something with the IPN (which I have no clue what it is :) then my question is, does WA have a tutorial for using ecart (I am a monthly subscriber for the extensions) to make whatever changes I need to make to do this and make sure my client still obtains order history information? They don't need to know about inventory levels, but order history is important, including "pending" and "completed" as well as the confirmation email(s).