Your free insertions can be used for new listings, but they are also used up when you existing fixed price listings roll over each month. If you had 9 available free listings, listed one new item, and have two left, then apparently 6 of your existing listings rolled over today.
For instance, a listing that began on February 26 or on March 26 will roll over tomorrow (April 26) and if a free insertion is available it will be used for that rollover; otherwise, you'll be charged a basic insertion fee (35 cents if you don't have a Store subscription). It might be time for you to consider upgrading, and subscribing to a Basic store (at the month-to-month rate).
http://pages.ebay.com/stores/subscriptionterms.html
