It's amazing what you can save shopping around, especially if you stay clear of car stealerships.
30,000km plug replacement:
Dealership: $1200, plugs & labor to change.
Champion Australia: $96 plugs only (and none in Australia).
US shopping, USD 1.60 per plug!
Total with shipping, my own labour (1.5 hrs), $40. That's a huge saving!
They are only basic copper plugs. Had they been iridium or platinum like the larger 370 cube SRT Hemi I would understand, but alas they are common muck copper plugs.