After you apply to the police asking for a permit, you can buya gun in Pennsylvania.
AK-47 models are not fully illegal, it's that the fully automatic variants are restricted to military usage and thus a typical civilian cannot get easy ownership of such rifle. However, semi-automatic versions are legal for civilians to own. If you live in a place where semi-automatic rifles aren't restricted, then you're in luck to getting the semi-auto AK-47.
18.
Yes
18 theres alot of money and stuff involved to own one legally
In America, yes. You must have the proper paperwork and taxes paid.
Provided you follow all the appropriate laws, yes.
Yes, in accordance with the provisions of the National Firearms Act of 1934.
Yes, provided the firearm itself is legally obtained.
You can. It is not against the law to own fully automatic weapons provided you follow all the rules. 21, clean criminal record, money to buy, CLEO signature, etc..
If you follow all the laws, yes.
The short answer is no, unless you have a firearms collector's licence. A fully automatic weapon is a restricted weapon and unless you have the correct licence you are not allowed to import them or own them. The collector's licence is difficult to get and restrictive.