While supplies last, in addition to the BOGO deal, and regular internet discounts and/or free shipping coupon codes, they are also including extra stuff in orders if you order uneven numbers. The BOGO deal is mix and match, but they have already packaged things in packs of two. I ordered 3 rotation and 5 lever servos. I got 4 rotation and 6 levers with no extra charge for the two extra servos and was able to use a 15% off and free shipping coupon codes.
Obviously not something you can count on, but if you needs servos anyway or the other EZ-Bits they sell, might as well do a ix and match so the individual types are uneven and you could luck out too.