Amazon is lowering the cost of a One Medical membership for Amazon Prime subscribers, shaving $100 off the annual fee to $99 a year. The step is the latest effort by the e-commerce company to mesh its chain of doctor's offices with its retail services.

Amazon already runs a web pharmacy and a telehealth service called Amazon Clinic that uses third-party medical providers to help treat less serious conditions, like pinkeye. It's also testing a service to drop medications on its pharmacy patients' doorsteps via drone in an hour or less.

A Prime subscription runs $139 a year, also offering streaming services and quicker shipping.