bro,
1. the battery you got was compatible, usable & will not damage your camera.
it is an EN-EL3E battery configuration. yes it can be used. just like exhaust brands for cars, there's HKS, FUJITSUBO, SEBRING....& the list go on....but why do car owners wanna use these brands instead of original exhaust that came with the car? it still will work, so there is no element of danger here. I have frens using oem batt, same model as the en-el3e, on their D80 for more than 1 yr, no worries, no ****-up. so there you go i hope your mind is at rest on this issue.
2. yes i agree the camera body will have to come with original battery in most cases. however, you need to clarify with the dealer before purchasing. the deal at that price, what are you entitled to? ..........remember when purchasing from retailers like these, they manage how each camera set should be sold, bundled with what items. it's their prerogative. so when you agree to part with that sum, it's seen as you agreed to purchase according to their terms. therefore, terms & conditions of sale MUST BE CLEARLY AGREED UPON by both buyer & seller, as the investment is more than $1000.00, not $100.
3. competition is tough in the market for all kinds of retailers not particularly camera retailers.
the camera body, charger & battery issue is really up to dealers to package. hence, the obvious price differs from one retailer to another for the same sort of camera...because its really a cut throat competition.
MORAL OF THE STORY, BE AWARE OF WHAT YOU'RE PAYING FOR
its a matter of how much research you do first, understand what you're paying for & be contented with your decision .
otherwise, these dealers can also point back the finger at you by saying you misinterpreted their sales pitch & cry wolf.
no offence bro, just be extra cautious in your future purchases, coz you're gonna be spending on more accessories like lens, filters, bags, tripods, batteries, all that extras
above all, congratulations on your new D80, hope you enjoy your new machine
cheers!