1. about 60-150 depending on what one u buy (pattern or genuine ford)
2. allan keys, screwdriver, gasket sealer
3. its very easy, drain cooling system, take hoses off, undo allan bolts, take pump off, clean old gasket off block, put new one on (might as well get new thermostat at the same time, and fit it)

the key issue is preparation. Make sure the block is all clean and flat and it shouldnt leak