Wiggle.com, evanscycles.com normally have good prices on Ortlieb (they don't ship Ortlieb to USA anymore, but you should be good in France).

The Plus fabric is lighter than the Classic, but many choose Classic models for their lower price.

Ortlieb also makes an economy version of Roller Classic panniers, called Roller City, here:

http://www.ortlieb.de/p-liste.php?pt...tasche&lang=en

http://www.ortlieb.de/_prod.php?lang...backrollercity