Most contact lens wearers don't know this and the eye care profession is not going out of its way to tell anybody. In 2004, President Bush signed 'The Fairness to Contact Lens Consumers Act' to allow you to shop around for the best price on contact lenses.
The Act clearly states "Prescribers must - give a copy of the contact lens prescription to the patient at the end of the contact lens fitting - even if the patient doesn't ask for it." It really says just that. For a government document, it can't get any clearer.
Anything short of being handed your prescription, with a smile, is self-serving and poor service by your eye care professional. If your OD makes you feel uncomfortable about saving money, maybe it's time to consider getting a new OD and start saving money!