No one's built a nuclear weapon in over 15 years, except for experiments in North Korea. America hasn't built any for almost 40 years.
That said adjusting for inflation, it would cost roughly $150,000-$200,000 dollars; less if you buy preprepared fissile fuel.
Germany has not made a nuclear bomb.
To make a nuclear bomb, you need the fissionable material such as a Plutonium239 isotope, an explosive to start the nuclear chain reaction, a detonator, and a pusher.
Albert Einstein did not make the nuclear bomb. Oppenheimer did.
To make deadly Nuclear bomb
YES
Explosiosives.
Plutonium + Weapons = Nuclear Bomb
Go and find out your self.
No, USA did.
If you are a smart guy, you can make a nuclear bomb, or a nuclear reactor...
plutonium + weapon
United States of America