The flat amount or percentage you pay for a covered service after you satisfy the annual deductible, if any. Please note many plans offer co-pays that are separate of the deductible. In other words, it may cost you $30 to visit the physician and an additional 30% of a service such as a blood test. Co-Pay plans were introduced to California plan designs about 15 years ago in response to consumer responses. Office visit co-pays are clearly spelled out in a plan design. Some insurance companies have re-designed their plans to include a percentage co-pay rather than a fixed amount.