Prescription strength Omeprazole, a drug that has an OTC counterpart, before insurance: $118. After insurance: $3. I found this out when this Walgreens wouldn't take one of my insurances, despite other Walgreens having no issue with it. Despite the same insurance working fine for other meds, in this Walgreens.
Luckily, I have two other insurance cards to choose from, and one of those worked for it.