My German Friends here.......Is it TRUE that Germany has a 5 euro coin, that is only good in GERMANY? What's the deal with that?
More or less. Several european countries have minted 5€ coins, but from all I could find, at least the German coin is only legal tender in Germany. However, its collector's value exceeds its legal value - the 2018 edition I found trades for 15€, so anybody would be really stupid to either use it to pay 5€ of value with it - or refuse to accept it as payment for 5€ value. It is (apparently) mainly intended as both a commemorative coin (well, supposedly...) as well as a showcase for German minting technology (it incorporates a translucent polymer ring between inner and outer part, the colour is different for the different years). Giving it a nominal trade vallue probably both gets the attention of a wide part of the public as well as circumventing some legal and tax issues.
There are special 2, 5, 10 and even 25 EUR coins for collectors (on "btn-muenzen" website i.e.). Those coins are not a currency in circulation, but can be used to (officially in Germany only) pay with - though it wouldn´t make sense, because they are much more expensive in purchase than their nominal value.
I lived there for 5 years after the Euro was "introduced" (read as: forced on them). I've never heard that.
You read wrong. A Euro can be used in any nation that accepts it.