You can search the net for what you looking on guns America or other similar sites. You can purchase from anywhere in the USA but it must be shipped to another dealer in your state. The terms of the USA service rifles I would recommend you get a book about the M1 carbine.
There were many different variation and contractors. Those made Rock-o-la are the most expensive. The M1 Garand can be purchased from US government directly if follow their criteria. Basically you need to be a member of the NRA/CMP affiliated gun club and fire 80 rounds in matches. Both US rifles have become very expensive lately.
They go anywhere from $500 to 2000 range. Beware of rewards guns that were cut in two and welded back together. Again read up on rifles or any other gun that you might want to get. Make sure you know what you are looking for when you find a gun. Most important piece of information of all is to make sure that you see all the right documents on that piece of firearm. Military Mausers of all types are cheap and plentiful.
Some are under $200 and others under $100. I would go with WWII vintage rather WWI era rifles. Again first stop is picking up a book on Military Mausers. They were made and used all over the world. The British SMLE is plentiful with newer ones that fire .308 wins the most expensive in the $300 to 400 ranges.
Older ones in .303 are $150 to 250 ranges. Again there were many variation get a book on collecting them. Russian Moslin Nagant are cheap and plentiful and under $100. The value of a Broomhandle Mauser is going to difficult to set considering it is just part of a collection and one of which I cannot inspect.
Additionally Rusty, there are other issues in regards to the model 1896 (Broomhandle) that are unique concerns to the collector. To begin with there are over 30 different models/variations of the Broomhandle and equally as many different retail values. I have no way of knowing which model that the firearm in question may be. Another issue that needs mentioning here is that the retail values are also going to vary due to matching stock/holster.
A correct matching set will add 40% to the value of the 1896. Non-matching stock/holster will add between $350 and $600. Also, over the years there have been large quantities of Broomhandle Mausers and Astra copies imported into the U.S. These are in fair to poor condition and have been offered for sale at relatively low prices mostly as parts guns. During recent years these very common pistols have been "converted" to "rare, exotic, near mint, original" specimens selling for four figures.
Since it is impractical to try to list 30+ values X about a half dozen price setters, I can advise you that a Standard Wartime Commercial model in "good" condition has a retail value of about $800. That said, prices for other variations climb as high as $10,000. A 1920 Rework would be selling for about $500 in "good" condition.
Post war models as low as $600 in "good" condition. There are some Chinese copies that sell for as little as $350 in "good" condition. The P38 is a very wide description of a host of Walthers. The retail value on such a gun is anywhere from $350 and up depending upon a list variable of which I have no way of knowing for certain. The best advice that I can give you is that usually a person who has such a collection for sale with some items having special significance, they can provide a copy of an independent qualified appraisal of at least the firearms with collector interest such as the Mauser and Walther mentioned. I would ask for such documentation before making an offer to purchase and/or offer to hire/pay for an appraisal you if the owner cannot provide same.
This is the best protection that you can obtain for yourself.
Victor Epand is an expert consultant for http://www.CombatCloth.info/. CombatCloth.info carries the best selection of combat clothing, gear, and accessories on the market.