How much does it cost to keep a pig?

A recent conversation on one of the pet pig email lists I'm on focussed on how much it costs to keep a pig ... this was brought up in light of one big sanctuary's general sponsorship request of $20/mo/pig. Here is a bit of that:

Well for a pot they average the care to be 4000.00 for its life time with no huge vet bills. For farm pigs it is higher. But if we get 20.00 per month for either, it will average out over time to 3840.00 for 16 yrs so it's in the ball park for a pot. It does however mean that if the pig needs surgery then the sanctuary has to eat the bill its self. But over the years we've found that people will give 20.00 a mo easier then asking for more upfront or or the long haul. Twenty seems to be the magical number but I have yet to have any monthly pledge last for more then just a couple yrs tops. But it does help.