How much it cost to replace an ignition switch on a 1995 ford Taurus?

It could cost up to $1000. Probably around $800 for the 1995.

I would expect a whole lot closer to $100 or less. It is an easy replacement - and no reason why you couldn't use a part from a auto salvage/junkyard.

Update: I just checked and an ignition switch is only $17 at Autozone.

Wherever you buy the part from should be able to help you find it - there's only 2 screws and a couple of wiring connectors.