Clarify to them that your usual price is much higher, but you are simply giving them an introductory offer. Your goal is simply to get the attention of your potential customers. However, be sure you can at least cover all your costs, including some value for your time. Also ask them to serve as reference for you in the future. To get your feet wet, volunteer your services.
Some work beats no work, and work tends to beget more work.
There's nothing worse for your morale than having your skills lie dormant. Valued volunteer efforts can turn into paying efforts. It helps get the word out about your business. Many volunteers find their experience leads to paying contracts or orders. At the very least, volunteer efforts can be a source of experience, contacts, and references that you can leverage into their business you might not otherwise know about or be able to get.