Learn Finnish: Minulla on nolla euroa.

Finnish doesn't have a direct verb for 'to have'. Instead, it uses a location case to say something is 'at' someone. Minulla means 'at me', and on means 'is'. So, the phrase literally translates to 'At me is zero euros'.

Why is the word for euro written as euroa instead of just euro?

In Finnish, any amount other than one, including nolla (zero) and larger numbers like 100 or 1000, requires the noun that follows it to be in the partitive case. To make euro partitive, you add an -a to the end, making it euroa.

English uses the plural 'euros' here. Is euroa plural?

No, euroa is the partitive singular form. In Finnish, numbers are followed by the singular form of the noun, even when we would use a plural in English. The plural partitive form would be euroja, but you do not use it after basic numbers.