On turn 20, since I had 11 silvers (thank you, dear my opponent when i went margrave+masquerade ^^) and a trading post in hand and +$2 from swindler, and there are 3 provinces remaining, I say myself : "why not getting all of three ?" yes, but I needed an extra +$2... so trashed I an estate and a province, so $24 to spend.
Yes, BUT... i had only 2 buys !!! And no more ! I remembered buying 2 margraves, but this was everything.
And I eventually won by only 6 points. If he had the money to catch the last one... well, I would still have won because of the difference of turns taken.
But this is to say, when you have lots of money to spend and a huge confidence in yourself because of your engine... don't forget your buys ! I'm not so proud of my mistake ! I still wanted to tell you about it !