Hi ccsillyone,
Purchasing masks and machines can be done either locally at a medical equipment provider, or from an online provider.
There are advantages to both.
If you are interested in online providers, you might try using
www.froogle.com which is a product feature of Google. You will need to search for specific names, like cpap masks. But prices from different providers will be listed. But buyer beware. Be sure you are comfortable with the customer service and understand their policies. A local provider might be helpful and even let you try on masks. But online providers can be helpful too. You need to purchase your equipment where you feel most comfortable.
Linda