Plural for euro

[Ella]

Dear Alan and Torsten,
tell me, please, when a plural form of a euro is euros and when it is euro.

[Michael]

Although I'm neither Alan nor Torsten:

I suggest writing euro (100 euro)
"Euros" seems not to be official spelling.
(check EU website for further information)

Mike

[Ella]

Thank you, Michael.

[Torsten]

I think when you add the currency to a price, the plural form is used (The car costs 30.000 Euros.) However, I also agree with Michael - sometimes the singular form can be used in prices (this car is about 30.000 Euro.)
In compound nouns you use the singular form:
This is a two million Euro contract. Also, it probably makes sense to use the plural forms in questions like How many Euros have you spent on your education so far?

TOEIC listening, photographs: Working in a muddy field