I suspect there would be some decrease in the prices; after all, companies are suddenly not liable for corporate income taxes (or personal income taxes for those that file that way). So there is some savings that they presumably could pass on to the consumer.
Yes there is some. But to get to 23% embedded taxes you must include the taxes paid by all the employees and owners. The fairtax does eliminate taxes like the employers share of the payroll tax and corporate taxes and such that could be passed to the consumer, but that totals about 8% of costs not 23%.