Chewy and Amazon both selling Greenies at a significant discount. According to CamelCamelCamel normal price is $33.99
Chewy and Amazon both offer additional Subscription discounts:
https://www.amazon.com/GREENIES-Dental-Chews-Value-Petite/dp/B006W6YHRS/ref=sr_1_4?s=pet-supplies&ie=UTF8&qid=1539648015&sr=1-4&keywords=greenies
https://www.chewy.com/greenies-petite-dental-dog-treats-60/dp/35510