I'd imagine that if SE, with all its programmer people, could implement such an anti-spam scheme, they would.
But your rep for links is interesting. Even 100 would work. Any SE member from other boards would get 100 rep just for joining Money.SE, and see no issue. Only those brand new to SE would have this, a minor nuisance, but a great thorn in the spammer side. We'll look into this.
Just spent some time at the Teacher's Lounge -
Their experience is that changing link ability doesn't affect spam as well as we'd imagine, the post just appear as text, i.e. the spammer isn't discouraged enough, and still posts.
There is, however, a bot for early spam detection, and they requested it be activated on Money.SE. It will create alerts at http://chat.stackexchange.com/rooms/35068/smoke-detector which I just opened.
That room is now live. In theory, it will bring these to our attention faster for deletion.
Update - the filter is in place, we are alerted via the room, but the deletion is still manual.