Walmart $6.97, free shipping with W+. Not sure what the shipping cost is, otherwise.
https://www.walmart.com/ip/Simple-Green-All-Purpose-Cleaner-Refill-67-oz/22301217
This is what it shows for me, since I don’t have W+:
(Please note: I don’t work for Woot, I just volunteer to help out here on the forums.)