A NIB "standard model" 391 sells for around $725, give or take $25 or so. That's the current Beretta auto offered.
As 390s are not a current model, you can occasionally find a field model with synthetic stocks and 3 chokes for $550 - $600, depending on locale. A local sporting goods chain where I live has them for $589, while the Walmart version here (only 1 choke) sells them for $529. Some stores sell a model called the 3901, which is a grey synthetic stocked 390 with the rounded sporting receiver that some rumor to be a general offering in response to the Walmart guns. They run in the $560 - $620 range around here.
BTW, chrome bores are a Beretta standard.
Bud