I haven't had to do this as I paid the fee up front when I started the application.
Some local offices will let you pay the fee when you show up at landing interview, other amy want you to pay before you arrive at landing. I think it depends on each office's ability to accept payments or not.
If I had a choice, I rather pay online ahead of time and keep receipt. Take the receipt with you as proof of payment. However if you pay early, then the letter will not ask you to pay the fee. However if you didn't pay the fee, the landing letter will tell you remind you to pay the fee. It may instruct you in how to pay for it. Ie "pay the fee at landing appointment" or "pay the fee online before landing"
Screech339
Thanks Screech, I want to pay online, but I wanted to know if scheduling of landing date depended on payment of the fees?