i would like to know would a wholesaler pay for a bottle of barbeque
sauce and/or what kind of markup would a retail grocer expect from
this type of product?

My wife and I currently own a small retail grocery store in vermont. 
I can tell you from experience that mark-ups range from 20-25% for
most common grocery items.  There are always exceptions, but people
will pay more for an item that stands out (in packaging, flavor
etc..).  Good luck.