If you are looking at NEW 28ga. O/U's and want to stay at less than $800 I wish you the best of luck .
Consider a CZ , or a SKB . Hunt the used gun market , with some luck you can find older Rugers , Brownings , Berettas , and Winchesters in the $1200 range .
Remember the Yugos ? Lots were sold because they were cheap . And folks got exactly what they paid for .