done free once for charity event of a corporate org.
they provided me everything that i needed (meal, transport, film, batteries).
it was shoot-n-go and they take care the rest like dev and process.
since i moved to digital, my slr was in the dry cabi and they even want to pay the cost of general servicing my slr at canon before the event, but i rejected the offer.
maybe it was lady luck smilling at me.
every now and then, when they have corporate event, then will ask for my service. and i do charge them.