I know you're trolling, but I'll respond anyway.
According to canon law - the law by which priests are supposed to live - no priest is allowed to excommunicate anyone.
A person can either be automatically excommunicated by their own actions (for example, by having or paying for an abortion) or they can be excommunicated formally by a bishop, which is an involved process that requires a formal procedure, usually including a canon law trial.
No priest is permitted to excommunicate anyone for failing to kick extra money into the till. Not only is this not an excommunicating offense - it isn't an offense at all. On top of that, no priest is allowed to excommunicate anyone for any reason. He doesn't have the authority.
If you noticed, the tiny handful of priests who were abusers hid their actions and moved around a lot. Why - because they knew they were breaking both Church and secular law and they were trying to keep it hushed up.
There is a difference between concealing a crime and boldly proclaiming that you have committed a crime. If a priest or his parish office sent out a letter saying that someone was excommunicated for not increasing their Sunday offering they are telling their bishop two things: (1) I am just as powerful as you are within the Church (which is something no bishop, corrupt or not, will tolerate for instant since it is a personal attack on his jurisdiction) and (2) I can break canon law whenever I want, in fact I'll put my crime in writing, and there's nothing you can do (this is like a public slap in the bishop's face).
Let's use an analogy - it's like a Congressional aide in France on official business, and a cabdriver overcharges him, and he sends a letter to the French consul saying that the US has formally declared war on France and that he was personally authorizing military force.
The Congressman who employed him would be beside himself.