This actually seems to work with any Roomba, but the 690 seems pretty popular. It also takes a little work (HINT: Google/Bing/Siri: "20% coupon for Bed, Bath and Beyond") for you to sign up for a free 20% off on-line coupon that is good for 48 hours.
You can also sign up HERE [bedbathandbeyond.com]
, but I believe you'll have to pick it up at the store. Although if you're like most people and you have 13 of those coupons from your mailbox you can just go to the store and pick up the Roomba.
$374.99 - $75 coupon = $299.99.
FYI I used the coupon in the store two days ago and they didn't blink.