Two hundred rupees are/is a lot of money.

2 answers

It’s better to rephrase a bit —

Two hundred rupees are considered a lot of money.
Webpages with good explanations about this.

Basic rules about subject-verb agreement:
http://grammar.ccc.commnet.edu/grammar/sv_agr.htm

Also this:
...remember that the number (singular or plural) of the subject, not the predicate, determines the number of the verb.
from http://grammar.ccc.commnet.edu/grammar/plurals.htm#collective_nouns