No, prefixes, as in kg. Money, as we have seen in this thread, does not use SI stuff at all, so talking about it this way is awkward, since $100k appears to have an SI "suffix" when technically it carries an SI "prefix." But US people usually do not say "100k USD"; they believe $ always means USD. People in other countries using $ know their dollar sign is likely to be confused, so are more likely to say "100T ZWD" etc.