Usually, attributive nouns in English are singular; for longer treatment, see How do you use plural or singular form of an adjective?.
You may consider units to be a variety of attributive noun, though there are additional guidelines, for example, for measurements. Different style guides define the guideline in different ways; the Oxford Style Guide says
Note that units of measurement retain their singular form when part of hyphenated compounds before other nouns
a five-pound note
a two-mile walk
a six-foot wall
a 100-metre race
Integer and decimal amounts, on the other hand, are always plural if not exactly one. (Varun KN stated this in another way.) Thus,
- 1 inch
- 0.57 meters
- -3π radians
- 62 degrees
- 0 rupees
Thus, you have either
- a zero-rupee note
- a note worth zero rupees
Also see at EL&U