Thanks, Jason. I am using the Free Tools. I'm not using Add to Cart, just the Buy button. Can I change the "amount" field in the code and get the same result as you described above? I tested putting 0.00 in the amount field and what happened is that I was allowed to change the amount when I got to the Paypal page. Should I just go with that?
Also, Paypal advised me that I should enter the shipping address on the client's website rather than on Paypal - this is above my head! Am I now going to have to set up a database and online form for the shipping address?