Please do not take any of what I say as offensive, I just have a small retail operation to help pay for my "shooting habit" and also have been posting on forums since they started. From my experience of personal "duh's" and watching other's get "duh'ed" from being less then wise.
Anyway. The "Auction" sites are a business, and if you think of them soley as business and nothing else you know why. Business has overhead (cost of doing business) and without the margin in sale you will be soon out of business.
There is always, always, always, a reason for a discount, cheap price, good deal and REMEMBER your undying gratitude has nothing to do with it.
My other full time job will involves me in theft, fraud, and internet deception. You would do very, very, very, little or nothing by internet if you have seen the numbers of folks getting ripped off, lousy product, miss representation, and identity theft that targets those with the "too good to be true" and the "cheaper over there" mindset.
I have been stuck a few times (and probably will again as nothing is 100%) but also have done rather well and anyone who knows me from other forums knows I do not play any "retail games" but over 7 years (internet), 20 years total retail, and 3000 plus internet transactions but also learned the quite a bit hard way from my being "greedy (too good to be true), and not learning from or using my experience and other's experience. So again, what I say is from my clients and my less then successfull transactions.
Know your seller. Take the time for a phone call if on the forum at least on a gun. You can learn a bunch from tone, voice and inflection. The seller also finds out if the buyer is not a low life. If the seller/buyer will not at least take a call, there may be something wrong on a gun (you know you are dealing with a person and not a one timer rip off).
Written communication is many times written MISS communication.
Parts are another story.
New is new only from a retail operation and from a person is preowned or used. Period. You would not believe how many NIB guns from persons have so called "factory" slide stop scratches, dented sights, marks from multiple mag insertions, etc. So what you are buying from a person. No customer service or warranty. Expect that.
Shipping, when mailed if the buyer wants to make sure he gets it pay for Priority Mail with signature at least. You get or request to get a track. Surface mail will get to you 99% of the time but the one time who is responsible........Sender, USPS, or You the buyer.
NO civil or criminal recourse across states as the dollar amount is too small for a civil remedy or criminal action. Been there, done that and a few of my clients got their T-Shirt that way.
Shipping is expensive for both the buyer and seller, UPS for some of the high end products cost as much as $90. Buyer or Seller pays, Still, insured and gets there is the best way, not the "cheapest" way.
Product whether guns, parts, or whatever will move when the person who wants it see's it. I have posted a few parts on Gunbroker that were there for 6 months, so what. It sold when the guy that needed it saw it. $12 for a "take off" trigger, $27 for a SIG 357/40 mag in bag. $569 New from a known FFL dealer, for a Thunder Ranch .45 acp revolver shipped (I missed that one). All sold when the party who wanted it saw it. Were there other post's or ad's possible cheaper in other places, yes, but again, that is buyer's choice. And again buyer's risk tolerance.
Just from what I have been seeing lately, remember, take the time to check your seller. Remember also, do not be so cheap as not to insure your shipment some how. Your risk, no one elses
Again, best in your quest for the best value, not "cheapest" Price.