A deductible is the amount you pay for covered healthcare services before your insurance plan starts to pay.
Here’s how a deductible and co-payments work: If you go to the doctor, you might pay $30 at the front desk when you check in (co-payment) and then have a checkup and some tests that cost $425. If your deductible is $1,000, you will pay the full $425 + $30 co-pay for that visit and you would have $545 left to pay before your insurance begins helping pay for costs.
Note that some insurance plans cover services before you have met your deductible such as a co-payment amount for cost of your primary care visit. This amount still goes towards your deductible.