David
The obvious question is whether you are entitled to Income Related ESA? ESA(IR) is dependant on your household income, your savings and assets, and any hours that your partner works. See
Asset rule for ESA(IR) 24 hour work rule for ESA(IR) Unless you are receiving an IR benefit you have no entitlement to free prescriptions, I am concerned that your post suggests that you were.
You can either apply for an HC2 certificate based on low income or buy a Prescription Pre Payment certificate. Have a look at the following
www.nhs.uk/NHSEngland/Healthcosts/Pages/Prescriptioncosts.aspx Gordon