No they do not have to honor pricing errors. All they have to do is offer a prompt refund if they are unable to deliver for any reason. This is settled consumer protection law since 1975. Read the rules here:I actually think they are. error or no error. I know if you go in a store and if an item is priced wrong the store has to honor the price it is marked at.
I suggest calling the AG's office in your state to see if they have to honor the $99.
The pricing error in store rule you are thinking of is for bricks and mortar stores that post one price on the shelves and then have it ring up at the register as a different price. But even then they have an out for prices so low they are considered and error.
The idea that when someone posts a price on the internet that they must deliver to everyone who clicked on it is a complete myth. Many companies do honor pricing mistakes just for good customer relations, but no law says they have to.