Well, Kar98k91, if you are an American citizen. With no reason for prohibition from purchasing and owning firearms, (i.e. previous run-ins with the law, or severly poor mental health [which I dont believe that you be here in the first place if that was the situation]...)
You need to be atleast 18 years of age to purchase rifles and/or shotguns. You could find a K98k at a local gunshow if you live in a not so liberal area. But most likely your gonna pay through the nose at a gunshow. Check your local gunshops and pawnshops but always be leary. Do your research on what they normally go for,depending on overall condition (outside apprence and the bore)on todays milsurp-market. If you have your 03 FFL licsence then you are in luck. All you would have to do is to send a signed COPY of your 03 FFL to milsurp dealer like, Southern Ohio Guns (SOG) [they do have K98k's listed on their site now]. Might also want to check Century Arms, They are a big importer of milsurp goodness. In order to see the prices on their items, you'll need to have a copy of your 03 FFL on file with them and an account with them. Also check your local trader paper! I have purchased 4 rifles through mine.
Hope this helps -Kentuck
"Are you ready for the country?! Are you ready for me?!"
I got a k98 from mitchels mausers I think it was. They werent wartime k98's but they were made in 1945 I think it was incase the war dragged on and they needed them.