If I could just think of the thread on this we had before... I think it was a singer... lot of good advice in it.One thing, tho-- ask the funeral director to handle communicating the $$ part to the family, or any clergy officiating-- whoever is officiating at the graveside is theoretically in charge of you, as well. S/he should have been consulted by the family and should then have contacted you to explore availability, etc.
At least that's how it works here, unless the decedent is a member of the armed forces or other group where there is a tradition already established that people play for one another's passings. Too often, sadly, there is no one left to play taps, either-- a boombox is brought instead.
~Susan