Your Special should really be a Special. Don't just say you have a product that is $9.99 if it has always been $9.99 and will continue to be $9.99 -- that's not a Special.
You can specify the beginning and ending dates of your Special, however, the Special will be displayed on the Home Page of your city and county for a maximum of 15 days from the date you post it. If you want to extend the Special beyond 15 days, all you need to do is amend the dates to reflect an additional period of time.
For example, if your Special runs for the month of March, and you post it on March 1st, your Special can reflect that it runs from March 1st to March 31st, however, on March 16th, it will drop off the Home Pages. To bring it back, you should change the dates to beginning on March 16th and ending on March 31st. This makes Specials more relevant to the site visitor.
If you ordered a special product, at a special price, that you do not normally carry, and when the last one is sold there are no more, this could also be a Special that site visitors might be interested in.