Unfortunately, their shipping charges have seen a big increase. Used to be that "club members" got free shipping on any order.
Now, club membership is up from $20 to $25 and one must spend $100 to get free shipping. I declined re-up.
So, shipping for one 4S pack cost me $16 (ground required, of course).
The 25% off was essentially wiped out.
Still like their batteries and warranty, so I bit the bullet anyway.