I've been shopping around for a pair of Ortlieb Back-Roller Classics, and I came across this deal from St Kilda cycles: $139 + shipping. For me, shipping came to $8, which makes this at least $40 cheaper than the next lowest price I could find.
There are limited colors available - asphalt and black and white - and it comes with the older QL2 locking system. However, from what I can tell, QL2 is still quite effective: the main difference is that the lower rail has a different design from the newer QL2.1 system, and the material of the fasteners is more abrasive.
You can see a useful comparison of the locking systems here: http://cyclocamping.com/blog/2015/07/15/difference-between-t…
For those who aren't familiar with them, the Ortlieb Back Rollers are a very highly regarded set of pannier bags. These bags can be attached to any bike with a rear rack. They are waterproof and (reportedly) indestructible.