You could ask a non-techie friend or relative to try a purchase and see how easy it is for them?
10 out of 100 or 10 out of 1000/people? Some people will never get to a successful checkout.
10 out of 10. :(
I agree with onepointone.
What we do for shopping cart functionality trials is have an item on the site that is in a unique URL.
We set item price at .99 cents.
Then run the order.
Just my 2 cents worth.
Posting "THIS DOMAIN MAY BE FOR SALE" on your site isn't exactly confidence inspiring.
From your other posts here you've indicated you have been selling online for years.
If they entered all their information on your website, does that include an email / phone number? If so, have you tried to maybe contact them to see what they might have experienced?
Is it the site in your profile? Not trying to be smart, but if there's any actual products there, I'm surprised you even had anybody find them.
This seems like a pretty easy one to fix... if they filled out all of the info, then contact them and ask.
Does your website show the shipping information after collecting their address? Is it too high?
Is it possible your website is sending the users to the wrong PayPal account? Maybe the users DID check out and pay...
Have you tested in different browsers? I've successfully made sites that work great in Firefox, but you load them in IE and some required Ajax thing just doesn't load. Oops.
Opps, it's not the one on my profile and this is a new commerce site. I've just changed the profile to the correct one!
We didn't collect email address because we wanted them to reach the Paypal page where they can key in the credit details immediately.
Well, I picked one item, checked out, picked the shipping state, put in a fake address with a zip, and it took me to the usual PP payment page, where it had the proper item and everything ready, which I assume would work like normal. So if something is messing up, it would have to be after that. If you haven't, I would call PP and see if they can find anything wrong with your account.
Now that I think about it... Why is there a full name and address page to fill out first? When they get to PP, they're either going to have an account already, or if they use a card, they're going to have to fill all the info out a second time, correct? You don't have it setup to auto fill from the first page somehow, do you? That could be your annoyance that sends them packing right there.
Oh, it's just so that we could calculate the shipping fees? But great point! I think I could remove the first and last name on the form.