30% off at Advance Auto Parts (includes batteries, up to $50 off, free shipping)
Use code HXDCBX. 8% cash back from TCB available too. It says it's for ship-to-home only, but the code seems to stay applied if you switch to in-store pickup and then checkout. I got an Autocraft Platinum AGM battery, Group H6, 760 CCA for $126.99 + tax (after core charge refund).
Seems like this code expires in an hour so try HXCPBX if it does. I used that to order last night.