I bought two Waterway wing nemo monofins thru PFI online store and it was very very easy.
Performance Freediving
I e-mailed Mandy and she e-mailed back and I sent paypal $ to PFI then waited about 6 weeks and got my two fins. They charged also only for 1 shipping bill of $65 for both fins so saved money there. You can decide if its better to go direct to Waterway or through PFI. I think if you go thru PFI there will be less chance of error on order, wrong size or stiffness or whatever and also, if you have some problem with the fin, you have paid PFI so they will try and fix it for you and will know what to do. There is nothing wrong to go direct to Waterway though its not like ordering a book from amazon.com, a bit more complicated.
Cheers Wes