The owner buys the mattresses wholesale through Mattress Firm's dealer connections, then the advertised price will include a guaranteed markup for the owner and a "flexible" markup for the salesperson.

Mattress Firms are no longer owner independently operated. They're all owned and operated by Mattress Firm and have been for a while. All the beds Matt Firm sells are set at a MSRP that is enforced across the industry to anyone that carries those brands (failure to do so will result in your ability to order being cut-off). The margin is in-line with that of Home Goods and (even though I dislike Matt Firm) there is no such thing as $1,500 dollar mattress that they paid $200 for on their showroom floor. The lines Mattress Firm carries are generally very very good beds.