Its not the cost its the life... god I am going to sound like even more of a freak but I believe when you take an animal even a "free" one you take on the responsibility for that animal for life no exceptions.
That means to me if something happens ( it does especially in this economic time I know) and you can't house/feed/ provide medical care or love and attention that a particular species requires it is your responsibility to rehome it.
Flushing is just another form of abandonment like leaving your dog on the side of the road with sure cruel death at the end.
Sorry - off my soapbox now.
