Do I have to sell my book at the price embedded in the bar code?

For example, if the bar code on my book has a $19.99 retail price, do I have to sell it at that price?

On the ItascaBooks.com website we CAN discount your book by a percentage or dollar amount.

But with our other resellers/wholesalers, the book does need to retail for the price that is listed on the cover/bar code.