AT&T Promotion for S8

I want to upgrade to an S8 from a S5 and currently trying to understand the promotions being offered by AT&T. 

I'm getting different stories. 

• One store (corporate store I think) told me I would get a min of $200 off the price of an S8 if I turn in my S6 if it's in good condition.  They told me this would just be a bill credit and I could not buy the phone outright - meaning I would pay MSRP - $200.  They told me I would have to do it via Next. 
• Another AT&T store - (which told me they were not a corporate store) told me that I would get the $200 as in store credit, but I would only be allowed to use it  to buy accessories.  I never by in store accessories because the prices are much higher than online.  This seems suspicious to me and was wondering if they were just trying to boost their accessory sales for their store.  They told me I would not need to do Next if I didn't choose to and could pay full retail of the phone. 
• Another corporate store told me that I would have to use Next but my trade in would not be a minimum of $200 and for an S6 I'm looking at $60 at best.  If that was the case, I would sell it privately.  
• The online chat told me I could get the $200 and take it off the price of the MSRP and I could buy the phone outright - meaning not via Next. 

Pretty frustrating that stores are not consistent with the promotions. 

Can someone tell me what promotions their are currently.  I want the cheapest price for the phone.