Hi Tunup.
Welcome to our Mattress Forum. 
It is great to hear you have already done some mattress testing and have an idea of what you are looking for!
I understand why their marketing feels deceptive to you. Their website offers discounts from 55% - 80% off which is usually a red flag and it reminds me more of liquidator businesses sales.
In many cases, the sale prices that are offered by most of the mainstream stores and major brands (and even some of the smaller ones) are often a gimmick. Sale prices of 30, 40, 50% or more off tend to be a major warning sign since nobody ever buys these mattresses at regular prices anyway. These “sale prices” are often meant to encourage you to buy based on a false perception of value or based on a sense of urgency when in fact they are often still very much overpriced based on the materials in the mattress. While good stores or manufacturers will occasionally have a sale … they will be discounted from selling prices that already have good value and be for a smaller discount and for a legitimate reason.
GhostBed already mentioned this but your own personal research is important when choosing a mattress retailer. If you still feel attracted to their offer, you may wish to investigate their “deep” discounts further; in case there is a valid explanation behind them.
Regardless of the retailer or manufacturer you plan to visit, you will want to confirm that they are completely transparent (see this article ) and you’ll also want to make sure that any mattress you are considering meets your criteria and the quality/value guidelines here. We also have this useful resource on choosing a great mattress outlet to help you in your research when selecting who and where to test and purchase a mattress with.
The better options or possibilities I’m aware of in and around the Charlotte, NC area are listed in post #2 here with the exception of Sleep Easy in Gaffney, which is no longer in business.
Hopefully, some other subscribers in your local area will see your post and weigh in with their findings.
Phoenix