It depends on where you are. In the U.S. in most states, nothing is required in the way of papework, and it's legal as long as both parties reside in the same state, however, you should check with your local authorities to be sure.
It means that a gun is in new, not used, condition.
no
Quality
Yes. If you lie on the 4473 and get caught.
From a previous question, I understand that you are concerned that a gun you purchased may have been used in a crime. First, buying a gun at a gun show really has no greater chance of that being so than buying a gun at a dealer's shop, or buying one from a local private seller. You had asked about registration- in MOST of the US, there IS no registration of ordinary rifles, pistol, and shotguns. There is also no way of knowing if a random gun was used in a crime. If you are concerned with a firearm having been stolen, contact your local police department, and ask if they will check your guns serial number against the computer listing of stolen property. They will usually want to have possession of the firearm when they do that.
Gun shop/ gun show
The cast of Buying a Gun - 1929 includes: Charline Burt George Burton Lupino Lane Wallace Lupino
No money, no gun shop nearby, felony conviction, underage
It MUST be made specifically for an air gun.
The Freedom Group.
If selling the gun is banned, then buying it before the ban is no problem. If owning the gun is banned then it does not matter when you bought it.
It really depends on the Manufacturer, what model gun, and if it is used or brand new from a store or from the Manufacturer. Look at prices online prior to buying a gun. If you have a gun and wish to sell it, I might recommend taking it to a pawn shop and have it valued. Or you could even just take the highest offer you can get.