Sorry I misread the title. I thought you were looking for suggestions, but I see now you are posting in the classifieds and looking for one that's available. Anyways, I recommend the 835, but don't have one for sale.
Walmart or even better Academy or Rural King has Remington 870 20ga for $279 with 21' barrel.....loaded with #9 TSS.......have it drilled and tapped for $50....added a truglow gobble stopper reddot for $75....pretty close to $400 range....