I have text like the following two example strings
this book was sold for 12.00 on 12.12.2010
he paid 12.12.2010 , and puchased an amount of 15.00
You could use
\d+\.\d{2}(?![.\d])
if all you need is to distinguish between dates in exactly this format and currency amounts in exactly this format.
This regex looks for the pattern digits, dot, two-digits but only if it's not followed by either another dot or another digit (to prevent the dates from matching).
Quick PowerShell test:
Update for short dates in the form dd.mm.yy
(just in case you need them):
(?