Originally Posted by
heckler
That seems pretty annoying if you're required to actually purchase the ticket first, before you know if/how much a C+ paid upgrade will be..
The rate is a flat amount. If you go through to the seat selection page, you should be able to select the seat and it'll tell you the amount to select it.
Note that DL is in the process of changing international flights to a "separate" cabin C+ fare like domestic flights already are.